OUTLINES OF THE GEOLOGY OF WESTERN MASSACHUSETTS.

TOPOGRAPHY. channels deeper. It is obvious that these exist­ details of fact which constitute the record are formations stand in their proper relative positions, ing conditions under which the plain is being described in the essay relating to each quadrangle. the oldest at the bottom. In order to follow this general description, destroyed are not those under which it was The greater portion of the rocks of the Green which is applicable to territory extending beyond formed. Mountains in Massachusetts were once horizontal ALGONKIAN PERIOD. the limits of the Holyoke quadrangle, Quadrangles To gain an idea of the manner of development beds of gravels, sands, clays, and marls, Origin of the In the usage adopted in this atlas the term the reader is referred to the following referred to- of the once level surface of the plateau, we may which became consolidated into con- rocks- "Archean" is applied to those most ancient crys­ topographic sheets of western Massachusetts: conceive the present process of gradual glomerates, sandstones, shales, and limestones. talline rocks which form part of the Greylock, Hawley, Greenfield, Becket, Chester­ wearing down carried to completion. They began to accumulate at a time remote in original crust of the earth and which ancient rocks 0 of this region, field, Northampton, Sandisfield, Granville, and When the streams shall have carved plateau- the geological past, when the region was invaded antedate and underlie the oldest sedi- Springfield, all on a scale of 1 mile to 1 inch. away the elevations now existing, the plateau by the sea. There had been land of an extent mentary rocks. Used in this sense notArchean- The Green Mountain range passes across the and hills will be reduced to a surface of very not now known. It subsided and the sea spread there may not be any Archean rocks in the region. State of Massachusetts, between the valleys of gentle slope, rising gradually from sea level. over it. During the occupation of the The reat The name "Algonkian" is applied to all sedimen­ _ the Connecticut Kiver on the east and Green Moun- Such a plain is called a peneplain, or, when district by the waters, which was pro- tSlgSs- tary rocks up to the base of the Cambrian, which the Housatonic and Hoosic rivers on worn to a uniform surface at the lowest alti­ longed, there were changes in the s!on' rocks are at present without known distinctive the west. It does not here include descriptlon- tude above sea, a base-level. In the course of height of the land and the position of the shore fauna and are usually highly crystalline. The mountains of great height, as in Vermont, but is development of such a peneplain the sea may line about the submerged area, and the sediments Algonkian period, as here used, is therefore equiv­ a broad plateau. On the west it is bounded by encroach upon its area. To the limits of the deposited in the sea varied accordingly. In these alent to the later portion of the Azoic of Lyell, a high, steep, and continuous scarp; on the east encroachment the waves cut away all low hills deposits were doubtless buried, as fossils, some of the Eozoic of Dawson, and the Archaean of Dana. it descends by a more gradual and undulating and fill hollows, producing a plain which is even the early forms of life of the Cambrian and Silu­ Washington gneiss. The oldest rocks of this slope. The western crest has an elevation of more uniform than any stage of the peneplain of rian types. Eruptions of igneous rocks also region appear at the surface in oval areas sur­ about 2000 feet. The surface is deeply cut by erosion, except perhaps the extreme case of a occurred and caused the intercalation of various rounded by younger strata. They have been laid narrow valleys, with a few rounded hills rising base-level. Such a wave-smoothed surface is lavas with the sediments. bare by erosion of the beds which once deeply to inconsiderable heights above the average level. called a plain of marine gradation. In adjustments of the earth's form during sub­ covered them. The line of these ovals extends The western and more elevated portion of this The former plain of the Green Mountain pla­ sequent ages, down to and including south from the Hoosac Tunnel along the crest of , i -< -i i. . -i -i ,0. -i . Chemical plateau lies along the eastern edge of Berkshire teau may still be recognized by one who stands the Carboniferous period,L ' the Cambrian changes*** physical of the plateau. The rocks belong to the oldest County and forms part of the Berk- upon its surface and scans the horizontal sky line a^id Silurian rocks were subjected to JTnTsnurian sedimentary system, the Algonkian, . . TT'ii -IT /» Berkshire shire Hills, but the greater part of the H'M<*> the which represents it on a level with his position. chemical reactions and to pressures rocks* and are highly crystalline. They ' o J: western por- rocks- upland occupies the western half of It extended evenly westward from the Berkshire sufficiently powerful to disguise or obliterate the consist of firm, coarse gneisses which gne?ssesand 7 ° limestones. Franklin, Hampshire, and Hampden plateau- Hills over the now deep Housatonic-Hoosic Val­ original structure of the rocks. contain minerals and possess structures counties. Its western edge is a continuous ley, to touch the crest lines of the Taconic Moun­ The sheets of sediment changed form in a not formed in the later rocks, and thick beds of divide from which nearly all its drainage is into tains, which lie along the western boundary of manner which can best be compared to the coarse and highly crystalline limestones with the Connecticut. Only at one place, in Hinsdale, Massachusetts. Down this surface flowed the crumpling of sheets of paper. The Chan esof many minerals, some of which are rarely found in does this line of watershed make a large bend to rivers which cut the upper canyon of the West- pressures to which the beds were sub­ later limestones, as chondrodite, wernerite, dark sediment' the east so as to throw a considerable area of field Valley in Washington and the Farmington jected were greatest from east to west. pyroxene and hornblende, and coarsely crystal­ upland drainage to the west into the Housatonic. Valley in Otis. Those who have most carefully They therefore forced the beds into folds running lized graphite. Considerable beds of pyrrhotite, The plateau is traversed in deep and narrow studied the aspects of the plateau are agreed that north and south. The folds developed as alter­ magnetite, and graphite also occur. valleys by the main streams and branches of two it was once a peneplain, worn down by frost, nate arches and troughs; as the compression con­ Because of the presence of these heavy lime­ principal rivers, the Deerfield and the Princi al rains, and streams. They.differ as to what part tinued they were pinched together, so that many stones, which were probably of marine organic Westfield. .The Deerfield River, enter- SKffi marine gradation may have played in modifying of the beds which had previously extended in a origin, we may assume that the whole series, ing from Vermont with a southwest- p a eau* its surface. In any case it formerly extended horizontal attitude came to stand vertical or nearly except possibly the hornblende-gneiss of East Lee, erly course, turns abruptly eastward. At the from the sea by a gentle slope to moderate alti­ so. From such positions they were pressed over was sedimentary, but we know nothing of the bend is now the eastern entrance to the Hoosac tudes. It has been raised to its present elevation westward, overturned, and many of the folds laid in limits of the sea in which the strata were spread. Tunnel. The Agawarn or "Westfield Kiver by earth movements, and these were no doubt as an eastward-sloping attitude. The folds were of CAMBRIAN PERIOD. gathers its waters by three convergent streams : gradual as they were extensive and mighty. various sizes, ranging from microscopic plications the Westfield River, flowing south from near the To follow the history of the landscape of to arches several miles across. In the deeper Becket gneiss and Cheshire quartzite. The valley of the Deerfield ; the Middle Fork of the western Massachusetts still further back into portions of the whole mass the rocks were so rocks of the Algonkian period had grown old; Westfield, flowing south by east; and the West the past, we must appeal to the rocks Landsea es confined, yet forced to move by such pressures, they had assumed a highly crystalline texture, Fork of the Westfield, flowing southeast. The as guides. Their record is transcribed JloScai that they were squeezed and thrust one fold upon had been strongly folded and deeply eroded, and last-named stream rises in a gap in the crest of under the next head, " General geol- perio s* another. Where this occurred on a minute scale, through many ages had stood as dry land, while the plateau edge between Becket and Hinsdale. ogy," but something of it may appropriately be as it did throughout the Green Mountains, the the atmospheric waters had softened and disin­ This gap is in fact a deep canyon, ample for the sketched here. rocks are divided into thin laminae, which some­ tegrated them to a very great depth. Then the occupancy of a considerable river, in the swampy The carving of the old peneplain of the Green times differ from the original layers in the sand land sank and the waters of the Cambrian sea bottom of which the headwaters of the Westfield Mountain plateau occurred during and before the and clay, and are therefore called schists. advanced rapidly over it, coming apparently gather to flow east and those of the Housatonic so-called Cretaceous period of geological history. In the course of this process fresh minerals from the southwest. All the Algonkian rocks of to flow west. It is clear that this canyon was This period was, relatively speaking, only a short crystallized everywhere. In the more clayey this region were submerged, and beyond a shore not made by the streams that now start there, portion of the later history of the earth. In the sediments the growth of minerals gave line much farther east the dry land of the period Growth of but by a large river heading far to the west and process of leveling, elevations of some amount character to the schist, which is now new miner­ extended where are now the waters of the north als. flowing eastwardly. were removed. We are interested to know what called by the name of the distinctive Atlantic. Such a broad advance of the waters The features of this plateau its general uni­ was their magnitude. From this Cretaceous mineral, as mica-schist. The more purely quartzose upon the land is called technically a Transgres- formity of slope when considered as a whole, the land and from that of the preceding period, the deposits were cemented by quartz, forming the transqression.3 These( < waters in their brian. . sea and hills rising above its' surface, the valleys Juratrias, sediments were carried down to the dense rock called quartzite. Limestones crystal­ progress over the sinking land washed SSSlSii incised in its plain these features and ©"slope! nTiis seas and deposited in extensive beds, of which lized to marbles, or, when they were clayey, into the softened rocks into clean quartz sediment- . . ., ... i and valleys their relations record episodes in the g,jjepla' some part still remains as sandstones and shales. schists containing pyroxene, hornblende, and other beach sands, clayey and feldspathic sands, and development of the present landscape. The volume of these deposits indicates that the silicates. The volcanic rocks have been altered pebble beds, and these became consolidated into For example, the canyon at the headwaters of hills which were destroyed in the process were into hornblende-schist and chlorite-schist, serpen­ sandstones, feldspathic sandstones, and conglom­ the Westfield River stands like a broken aqueduct of great bulk; perhaps they were mountains. tine, and soapstone; and they may have furnished erates. They are now metamorphosed, the first opening above the Housatonic Valley. The river But there is another line of evidence. The rocks the iron for small beds of hematite and magnetite. into quartzite, and the other two into a gneiss in which carved the canyon had its source in the of the Green Mountain plateau contain minerals All this is expressed in saying that the rocks are which, in many places, the traces of pebbles can west beyond the latter valley and flowed over a and are characterized by fissile structures that metamorphic rocks or crystalline schists. still be seen. These rocks, part gneiss, part con­ surface high above that valley's level. To restore develop only under great pressure, such as exists In the processes of mountain growth and glomerate, can often be seen to rest on the this condition the Housatonic Valley must be deep in the earth. Hence it is known that these removal, portions of the folded rocks which were upturned edges of the older Algonkian gneiss. supposed filled to the plane of the eastward-slop­ rocks which are now at the surface were buried deeplyL J buried have come to form the Evidences_, .. of. The coarse deposits formed near the eastern ing plateau. The narrow valleys of the Deer- several thousand feet at least. The upward surface. The upper parts of the greater foldin»- shore grade westward with considerable rapidity field, the Westfield, and their tributaries may be movement of the earth's crust which raised them, folds have been worn off. Thus the cut edges of into the Stockbridge limestone, which indicates conceived to have been filled in like manner. as the old peneplain was being carved, was the the upturned beds are now exposed, and any one that the shallow water became deeper and Thus there is restored an extensive plain, the growth of a mountain range. That range was bed appears at the surface repeatedly. An illus­ clearer a short distance to the west, where the original form from which the dissected Restoration destroyed in making the peneplain, and the tration of folded and partially eroded beds in calcareous deposits gathered. Just beyond the plateau of the present time has been pl^SLr- present range of the Green Mountains has grown simple relations is given in fig. 2 of the Explana­ limits of the region under consideration the rock worked out. The greater breadth and ace-aplain< on its site by renewed elevation and subsequent tion on the inside pages of the cover. The more has furnished fossils belonging to the first depth of the Housatonic Valley, which is carved erosion. Thus two generations of mountains are complex relations of the schists of the Green assemblage of organic forms yet discovered. recognized, and it may be that they were preceded Mountain region are illustrated in the Structure- in limestone, as compared with the narrow Deer- SILURIAN PERIOD. field and Westfield valleys, which are cut in by earlier ranges. Moreover, the history of the Section sheet of the accompanying folio. The gneiss, are due to the fact that limestone offers rocks themselves goes still further back, to periods greater folds have been traced by observing the Hoosac schist. Beneath a sea which was prob­ much less resistance to eros^pn than does gneiss. when the sea prevailed over the region. dips of the beds and by identifying the recurrence ably still expanding beyond the shores which bounded it in Cambrian time, fine-grained sedi­ It is the habit of streams to adjust their courses GENERAL GEOLOGY. of such beds as the amphibolite in the Hawley to lines of least resistance, along which the deeper schist. The minor folds are too numerous to be ment accumulated during the early part of the channels are excavated. The relations of the The rock masses which make up the structure made out, and the original thickness of the strata Silurian period. As compared with the older Housatonic and Westfield rivers afford a striking of the Green Mountain plateau are of many varie­ can not be determined with accuracy. Becket gneiss, the finer grain of the sediment and illustration of this habit. ties. They have been brought into their present In the accompanying columnar section, fig. 1, is the absence of iron and potash indicate more The plain in which these valleys are carved is relations by repeated action of physical and given the full column of the geological formations perfect sorting of the materials derived from being destroyed because it is elevated. chemical forces, and the resulting architecture is in the area here described. On comparing with adjacent lands. Such sorting is accomplished by The streams, having fall, are able to of very intricate. In the following paragraphs the this list the legend on the border of each sheet, waves and by currents which carry the finer carry away loosened rock material, and plain* general relations of the rock masses and the out­ the distribution and relative importance of each material farther from shore. The resulting sand­ they also use it as a tool with which to cut their lines of geological history will be stated. The formation will appear clearly. In this table the stone has now become a hydrated mica-schist. which often contains newly formed feldspathic carries large garnets, which are surrounded by stretches in a broad band eastward from the Ches­ volume and, like the material of the Rowe schist, minerals, particularly albite. It has films of green chlorite. Blotches of ter hornblende zone, and is crushed into many consisted of well-sorted sediment. received the name Hoosac schist, as mTca-ascehist, chlorite formed from garnets are also mica-schist folds, which in this wooded country covered with Hawley schist. A formation consisting of derived from ° like the Rowe most appropriate for its whole extent common in the rock. Beds of horn- mSrffer - glacial clays can rarely be unraveled. The thick­ highly ferruginous minerals is distinguishable in Massachusetts, but it corresponds to blende-schist appear more abundantly ginous' ness of the formation can therefore not be deter­ above the Savoy schist. The prevailing the Green Mountain gneiss of C. B. Adams, in than in the Rowe schist. The Savoy schist mined definitely, but the deposit was of great rock is a soft, chloritic schist abounding schist aend the Vermont Survey. This schist is probably of in carbonates-, . otP iron. andi magnesia,. and-i associated COLUMNAR about the same age as the upper portion of the PERIOD. SECTION. DESCRIPTION OF THE FORMATIONS AND THEIR ESTIMATED THICKNESS. in black hornblende needles, which are Stockbridge limestone to the west, and is partly The deposits of the Juratrias comprise four sediments, which formed during the same often gathered in sheaves on the faces of slabs. upper Cambrian and partly lower Silurian, though epoch, namely: the Mount Toby conglomerate (Jmt), a very coarse basal conglomer­ These sheaves are calledfasciculite. Many bands ate of slate and crystalline rocks, along the eastern shore; the Sugarloaf arkose the rock is so uniform throughout from top to (Js), a coarse, feldspathic sandstone and conglomerate (4660 feet), on the western shore; of hornblende-schist, some of great thickness, can and the Longmeadow sandstone (Jl), a medium-grained, feldspathic, ferruginous bottom that no dividing line can be drawn. sandstone (1000 feet), and Chicopee shale (Jc), a sandy, carbonaceous shale (200? be traced for long distances. The abundance of feet), which accumulated in the central channel of the bay. These were cut through Rowe schist. By a gradual transition from one by volcanic eruptions of three distinct periods, the earlier two represented by the iron contained in this formation suggests the kind of rock to another, the uppermost bed of interstratified lava beds (350 feet) of Holyoke diabase (Jh) and the Granby tuff (Jg), possibility that it represents a period of volcanic an agglomerate of diabase (580 feet) interstratified with the sandstone, and the the Hoosac schist changes in a few feet into the latest by the volcanic cores and dikes of Blackrock diabase (Jb). activity, but no trace of a distinctly volcanic UNCONFORMITY overlying Rowe schist. This is the rock that The Bernardston series (Db) consists of a dark mica-schist, which is spangled with bio- rock can be found in it. A concentration of iron tite and contains several beds of amphibolite (1300 feet). This rests on quartzite (650 occurs in the region around the east portal of the feet) containing a bed of highly crystalline limestone (20 ? feet) full of Devonian in sediments may have been due to conditions Hoosac Tunnel and extends south across the State fossils. favorable for the separation of iron carbonate as UNCONFORMITY in a broad band which crosses the Boston and ^The Leyden argillite (SI) is a black, fine-grained, fissile slate. (300 feet.) a constituent of calcareous deposits. It may be, Albany Railroad between Middlefield station and also, that a part of the ferruginous Chester for­ the Chester town line. mation had become subject to erosion and thus The Rowe schist is a monotonous rock made up furnished the material for these well-bedded iron- of quartz and a white mica called muscovite. It bearing strata of the Hawley schist. is usually nearly all quartz, though the mica seems The Conway schist (Sc) is a fine-grained muscovite-schist, darkened by coaly matter, An interesting similarity may be traced between containing garnet, biotite, and staurolite, and is much contorted. It is represented the more important mineral because it is spread in on the east of the valley by the Ainherst schist (Sa), a rusty mica-gneiss, at times the sequence of formations of Cambrian and Silu­ fibrolitic and greatly impregnated with granite, and farther east by the Brimfield thin scales on the surfaces of the layers. The mica nbrolite-schist. (5000 ? feet.) The granite occurring in this area (Cw) was probably rian age thus far described and the suc­ erupted during the Carboniferous period, and cuts through all the Silurian and cession of formations of the Juratrias easily becomes hydrated, changing to the variety older formations. called sericite or hydromica, which feels greasy, period in the Connecticut Valley. The like talc. The rock is then a sericite- or hydro- later history can be more accurately mica-schist, and, like the Hoosac and read and serves to suggest the events of the Savoy schists in a similar condition, ?rlnAn to earlier. In the Juratrias period a rapidly taic-o°se> has been called talcoid or talc-schist. encroaching sea spread the coarse debris of sericite- In some occurrences the Rowe schist granite, forming a feldspathic conglomerate, which if metamorphosed would resemble the contains garnets and chlorite, and then The Groshen schist (Sg) is a dark, flaggy schist containing garnet and staurolite, and can not be distinguished from the is spangled with biotite. It has beds of gneiss interstratified. (2000 ? feet). Becket gneiss. Finer feldspathic sandstones Savoy schist above. The fact that the rock is followed in the Juratrias sequence, and these

largely free from feldspathic and iron-bearing UNCONFORMITY- would readily be altered to rocks like the Hoosac minerals, which develop from the clayey portion and Rowe schists. The trap sheets and broad- of a sediment, and is composed chiefly of quartz, spread tuff beds of the Connecticut Valley may indicates that its materials had originally been The Hawley schist (Sh) is a green sericite-chlorite-schist with beds of amphibolite and have had their earlier representatives in the manganese silicates. (2000? feet.) more thoroughly waterworn and sorted even than Chester amphibolite. The ferruginous formation those of the preceding deposits. It may be that in each of the two periods is followed by light- during the Rowe epoch the broader expanse of colored rocks light-buff sandstones in the Jura­ the sea gave the waves more efficient action on trias and the Savoy schist in the Silurian ; but the sands of that ancient shore, or that the mate­ later the iron of the traps affected the color of rials had more than once passed through the line the upper sandstones of the Juratrias, coloring of breakers during fluctuations of the shore line them dark red ; and similarly the Hawley schists before they came to rest in the Rowe deposits. may be rich in iron because the ferruginous rocks of the Chester contributed to their deposit. Sug­ The Hoosac and Rowe schists represent a great The Savoy schist (Ss) is a chloritic, quartzose sericite-schist with beds of amphibolite, changing toward the south to a feldspathic mica-schist with many intrusions of gestive as this correspondence of characteristics thickness of sediments which accumulated not granite. (5000? feet.) very far from shore, and therefore in waters that in the two periods is, it is not to be supposed were comparatively shallow. We must then sup­ that history repeated itself very closely. Diverse pose that the bottom of the sea in which these processes under different conditions may produce deposits were gathering was steadily sinking a similar results, and the facts described are not so little faster than the sediments accumulated, and, peculiar as to admit of one interpretation only. from the gradual transition, that this sedimenta­ Groshen schist. The schists described above, tion went on without interruption at the time of from the Hoosac upward, have been called the passage from the older to the newer formation. talcose schists by the earlier geologists. The Chester amphibolite. In the sequence of strata Groshen and succeeding formations were called by the Rowe schist is followed by a formation which The Chester amphibolite (Sch) is an epidotic hornblende-schist with beds of magnetite them the calciferous mica-schist. They and emery near the top. It contains beds of pyroxene rock, enstatite rock, and are much11 less metamorphosed, i i than, -i the,t Calciferousmica-schists, is peculiar in its character and mineral associa­ dolomite, and is frequently replaced by serpentine and steatite. (3000? feet.) L less meta- tions. It is a thin-bedded, greenish- older strata. This is indicated by the K)theed black, heavy rock, consisting of matted istics ofe " presence of abundant carbonaceous needlesn of1.1 hornblende i -i in a groundIP ot amphibolite. material, by the smaller size of the newly formed quartz and plagioclase-feldspar grains. Such a m minerals, and by the retention in good degree of rock is called an amphibolite or hornblende-schist. the original structure of the clayey sandstones It is a formation generally of no great thickness, from which they were formed. and, being tilted on edge in the present position The Goshen schist is altered from its original of the rocks, it appears as a narrow band. It is condition by the abundant growth of a white named from the unique emery bed at Chester, The Rowe schist (Sr) is a quartzose sericite-schist. Toward the south it is indistin­ mica among the sand grains of which it was at guishable from the Hoosac schist and is included with it. (4000? feet.) which occurs in it. first mainly composed, and the whole is darkened The mineral character of this formation is vari­ by a fine, coaly dust. In this are thickly spread able. As it is followed southward the amphib­ small garnets, staurolites, and spangles of black olite changes several times locally into a serpen­ mica set across the bedding. It breaks in flags a tine, abounding in dolomite. In the few inches thick, which are much used for side­ Alteration great bed in Middlefield the serpen­ walks. Many beds are almost purely quartzose tine retains the amphibolite structure, and are used for scythestones. and there is an abrupt change from amphibohte- Conway schist. This formation is distinguished serpentine to amphibolite. In Chester the east­ from the one below by the intense corrugation of ern border of the amphibolite is skirted by a bed the schists and by abundant beds of a The Hoosac schist (She) is a feldspathic mica-schist with numerous granite masses, 111black, coalyi andi micaceous limestone,v j_ Calciferousmica-schist of emery. From Blandford southward the which extend also into the Rowe schist. (1500 feet.) 1-111 i i i amphibolite gradually gives place to enstatitic which have changed at the top and dolomite, serpentine, and steatite. bottom into hornblende-schist for a few These mineral associations may have had their inches in depth. Blocks of this limestone origin partly in lavas and volcanic fragmental UNCONFORMITY- weather into peculiar forms, like anvils and plow­ deposits or in beds of ferruginous magnesian shares, the top and bottom being the resistant limestone. It would appear that they were The Becket gneiss ( b) is a white biotite-gneiss, at times grading into conglomerate. schist, the central shaft the easily dissolved lime­ (2000? feet.) derived chiefly from impure limestone, with a stone. Several thick beds of hornblende-schist possible admixture of basic eruptives, but the are also found in this formation. The lime­ relative importance of these factors is undeter­ UNCONFORMITY- stone and hornblende-schist distinguish it from mined. As a limestone occupying a place between the Goshen, in which these rocks are wanting. the sandy Rowe and Savoy deposits, the forma­ Eastwardly the rock changes into a coarse, rusty tion testifies to the presence of deeper waters The Washington gneiss (Aw) is a rusty biotite-gneiss carrying blue quartz. (2000? muscovite-biotite-schist, often somewhat felds­ over the area and the existence of conditions feet.) pathic. In the extreme south it maintains this favorable to calcareous deposition. character and assumes the aspect of a bedded Savoy schist. The Savoy rock is a sericite- granite or gneiss. This is due to the prevalence schist like the Rowe schist. It is usually of finer of true eruptive granite, from which, while it was FIG. 1.-GENERALIZED SECTION OF THE ROCKS OF WESTERN MASSACHUSETTS, SHOWING THEIR SEQUENCE still hot, alkaline solutions penetrated the schist, grain and more micaceous, and it more generally AND PRESENT COMPRESSED STRUCTURE. producing feldspars. The rock here becomes com­ the Cambrian period to the Carboniferous, it has bottom of the bay, as tar oozes and spreads from ton. They are formed beneath the ice as bars paratively barren of accessory minerals, though been noted that the older Algonkian rocks were a crack, and solidified in a sheet which may have are formed beneath water. Where bare bosses cyanite occurs near the base of the bed in fine more metamorphosed than the succeed- been 2 or 3 miles wide and about 400 remain the rocks are rounded and smoothed. . i i /-N Culmination Volcanic crystals. ing Cambrian deposits; that the Cam- feet thick in its central part. This is the They were also frequently scratched by stones The Goshen and Conway schists occupy an area brian and early Silurian formations, main sheet or Holyoke diabase. The anma dragged along in the bottom of the ice, and from wider than that of all the other formations com­ including the Hawley schist, had suf- per ° ' sheet was soon covered with sand layers, but its these striae the direction of the movement can be bined, but the two contract suddenly and do not fered more disturbance than had the strata of later thickness was such that it had shallowed the ascertained. The ice flowed over the plateau in reach the southern border of the State. Silurian age; and that the Devonian beds were less waters to near tide level, and thus occasioned a general course S. 35° E., and down the Connec­ Leyden argillite. This slaty rock is widely altered than any of the older rocks. The degree extensive mud flats. This was an area suitable ticut Valley from north to. south. Although this spread in Vermont, and enters Massachusetts in of metamorphism serves to distinguish these for the formation and preservation of unique course lay across hills and valleys which present Leyden, occupying the whole of the several groups of formations, and marks the fact records of the life of the time. The curiously irregularities of several hundred feet, the ice was turned aside only locally by the most marked town. It passes * south beneath the ceodepositsruscfay that the earlier ones were repeatedly disturbed, shaped and often huge reptiles of that age wan- Juratnas sandstones in. Greenneld/->, n and-i folded, and mashed in successive earth move­ dered over the mud exposed, at low tide, and their heights and depressions. Hence it is inferred Deerfield, and reappears in Whately, ments. Such movements raised land areas, possi­ footprints, being covered by the deposit of the that it must have been of very great thickness. where it is cut off on the south by the eruptive bly to mountainous altitudes, at several epochs next flood tide, constitute the so called "bird The till and glaciated rock surfaces in the Con­ tonalite. It is the least altered rock of the Pale­ during the Silurian and Devonian periods. Dur­ tracks" which have been found in such great necticut Valley are broadly covered by later sand ozoic column. Originally a black mud rock, it is ing or near the close of the Carboniferous period, numbers and perfection. and clay deposits formed during the epoch of now a black slate composed of a felt of micro­ however, occurred the culminating movements The sands had reached a considerable thickness glacial retreat, from flood waters of the Con­ scopic scales of mica inclosing small grains of which, to a still higher degree, folded and met­ over the first trap bed when a second outflow of necticut River. In the upland valleys similar original quartz and much coaly matter, derived amorphosed all the older rocks. It is associated the trap followed, icpresented by the posterior deposits accumulated locally in lakes dammed by from the organic bodies it once contained. When bed or Hampden diabase. Immediately after the the ice. in time and effect with movements Granitic most changed small pustules indicate the begin­ which affected the entire Appalachian intrusions. outflow of this sheet an explosive eruption took Deposits of the epoch of glacial retreat. After ning of garnets or black mica crystals, and it is mountain system and in New England were fol­ place, and blocks of diabase and pulverized lava the ice had so far shrunk that parts of Lakes and were spread by the waters over a broad area, the ground were no longer covered, stream*1 often netted with quartz veins. It is highly corru­ lowed by intrusions of granitic igneous rocks , 7 . -, occasioned gated, and where by pressure a cleavage structure among the sedimentary formations. The granites forming the Granby tuff bed. A third period of the abundant waters from its continued Jjr«« ice was produced it makes good roofing slate. At its are composed of quartz, po|ash feldspar, and volcanic activity followed, during which a line of melting were drained off to the south­ contact with the eruptives it is changed into a mica or hornblende. On account of the propor­ small volcanoes broke out along the old fissure east, down the slope of the plateau. chiastolite-schist, or even a chlorite-gneiss. tionately large amount of quartz which they con­ beneath the bay. The area was next the scene of The broad valley of the Connecticut was the The deposits of the Groshen and Conway schists tain they are called acid rocks. They are thus dislocations or faults, by which the mass of sedi­ main outlet of this drainage, and as the country and Leyden argillite make a continuous series, contrasted with the so-called basic igneous rocks, mentary and volcanic rocks was divided into great then stood nearly 200 feet lower than now, the separated from formations below and which contain little or no quartz and much iron, blocks, often extending north and south. The fall was slight and the waters spread in a succes­ above by considerable unconformities. conweanyand such as the Juratrias diabase described below. blocks slipped one past another along nearly ver­ sion of lakes. The central trap ridges divided They doubtless were laid down in a The acid granitic rocks, while intensely heated, tical planes. In these dislocations the strata were the waters into three separate bodies, which I . -. i . » sea having boundaries and history dit- melted or forced their way up through the already generally tilted eastward. have called the Montague, Hadley, and Spring­ ferent from those before and after it. folded strata in huge domes several miles across, Upon the map the faults which bound these field lakes. The tributaries sent great sand and Their limits on the south and west are success­ which sent out a multitude of dikes, like branches, blocks are clearly indicated where they cross the gravel deltas out into these lakes, and fine thin- ively narrower, the Leyden, the latest of the into the surrounding schists. The rocks now at the trap ridges. They are approximately Faultingof laminated clays, in which arctic leaves are found, three, lying within the Conway, and the Conway surface were probably intruded at considerable parallel, and run about N. 20° E., cross- SSSSgSE collected over their bottoms. within the Goshen, the oldest. Hence it may be depth, but have been since uncovered by deep ing the trap ridges at very small angles. The fact that the drainage west of the Connec­ inferred that the sea had shrunk northeastward, denudation. Their domes extend along the east­ They are doubtless equally abundant over the ticut Valley was southeast, while the ice front of or that the land had expanded in that direction, ern border of the valley from near the Deerfield rest of the district, but the sandstones include no the great glacier retreated toward the northwest, during the corresponding epochs. River to the south line of the State. peculiar bed which can be identified for long dis­ favored the clearing out of the main channels of The central portion of one of them, extending tances, and are so largely covered that the faults drainage and allowed the waters generally to flow DEVONIAN PERIOD. from near Whately to Northampton, is more basic can not be traced. Because of the unequal tilting off freely. Therefore, there were in that region Bernardston formation. Next above the Ley­ than the others and is called tonalite. Bordering of these blocks the outcrop of the main sheet has few glacial lakes or streams emptying in directions den argillite occurs a conglomerate composed in this is a granite containing black mica, and out­ a peculiar, lobed appearance, and the eastern sheet now abandoned, but some such transient bodies part of pebbles derived from that formation and side this is a granite containing both black and is broken into parts widely separated from each of water have left the evidence of their former deposited upon it near their source. Such a bed white micas. These extensive areas of granite other. In these movements, associated perhaps presence in flat-topped deposits of well-sorted is called a basal conglomerate. In and the bordering rock have been greatly cracked with general uplift of the area, the bay became sands and gravels over the surface of the plateau 0 Transeres- order that they should prod-ipee such g^0°rlalesea and the fissures occupied by coarse granite or land and the rocks were exposed to erosion. and at high levels along the valleys of the main pebbles, the Leyden strata must have JSffifXt.by pegmatite veins, which have been formed largely The subsequent history of the region, during streams. Thus by the damming of the Deerfield hardened and been raised to form a glomerate< by the intervention of water, and around the edge the later part of the Juratrias, the Cretaceous, Eiver near Shelburne Falls the waters of this shore line against which broke the waves of the of the whole complex mass these veins carry many Eocene, and Neocene periods, is Landscapes stream were sent south across Buckland, Ashfield, Devonian sea. Quartz veins also had developed in fine and rare minerals. Still farther out is a zone recorded only in the aspects of the SlEStas and Williamsburg to join the Mill River and the argillite. These changes imply the lapse of of immense quartz veins. landscape. In Cretaceous time the peno s' enter the Connecticut at Northampton, and the considerable time between the Leyden epoch and heights of the Juratrias uplift were eroded to an damming of the Westfield Little River sent the JURATRIAS PERIOD. that during which the sedimentary deposits were extensive peneplain, which now forms the level waters south across Granville and formed the continued by the return of the sea over this area. The events of the Paleozoic age, constituting a of the Green Mountain plateau, as has already broad sand flats that occupy that township. When The pebble beds mark the fourth unconformity in prolonged history of geographic changes, had been explained. This plain is also represented in the ice resting in the Housatonic Valley formed a the Paleozoic history of the province, the Cam­ come to a close, and a land not greatly Development the crests of the trap ridges in the Connecticut dam across the Hinsdale, East Lee, and Tyringham brian transgression having been the first, the break unlike the present in general configur- SiftJSS?-" Valley, the trap rock having maintained the level, valleys, glacial lakes were formed whose heavy 'at the base of the Silurian the second, and that ation had been established, when a new men " while the soft sandstones surrounding it were sand beds are still thrown across these valleys. separating the Hawley and Goshen schists the sedimentary record was begun in a bay occupy­ worn away. In consequence of the elevation of Many similar instances are mentioned in the third. The basal conglomerate and the deposits ing the position of the Connecticut Valley in the region after Cretaceous time and the activity description of the separate quadrangles. succeeding it were spread over Bernardston and Connecticut and Massachusetts. The shores of the of the ordinary atmospheric agents, the surface With the disappearance of the ice from the Vernon and are known as the Bernardston forma­ bay were the west scarp of the Worcester County had been engraved nearly to its present relief of drainage area of the Connecticut, the system of tion. They are now greatly altered ; the pebbles plateau on the east and the east scarp of the Green valleys and hills when the unusual conditions of lakes shrank suddenly to the present Cnanges have been mashed as if they had been soft metal, Mountain plateau on the west, and extended from the Glacial epoch were brought about. The his­ river. The old shore lines of these g££LShe and the whole conglomerate is locally changed to near Brattleboro, Vermont, to New Haven, Con­ tory from the beginning of glaciation is described lakes are now 380 feet above sea on epoch' gneiss. The gneiss grades up into thick beds of necticut. The sea waters rose to a considerable under the next heading. the north line of the State, 300 feet at Northamp­ height above the present level of the bordering ton, 180 feet at the south line of the State, and quartzite, upon the faces of which PLEISTOCENE PERIOD. there,-i is. muchi newlyic lormed j mica, Character of plateaus, and spread sediments brought in from down near sea level at New Haven. As fine nian rocks. Beds of limestone inclosed. 1 in these1 these elevated regions on either side of the bay. Glacial epoch. The landscapes of New Eng­ clays were deposited over all the bottoms of the quartzites still contain upper Devonian corals, The shoreward sediments on the east are land owe their generally rounded profiles to lakes, there can then have been but little current through them, and therefore little fall. Since crinoids, brachiopods, and other shells, although represented by the Mount Toby con- S>engVo°mlr°.f the effect of an ice sheet or conti- Advanceof the rock is so coarse-grained that cleavage pieces glomerates, and the Susrarloaf arkose SrowlTsand- nental glacier which spread over the then the land must have risen in the latitude of o ' ° . stones. Northampton nearly 200 feet. This has given of calcite more than an inch across can sometimes is the synchronous deposit lormed region in recent geological time. The glacien the Connecticut new power of erosion, and it has be split from it. along the western shore. The Longmeadow ice expanded from a center of accumulation Above these altered sandstones and limestones sandstone was deposited in the shallower and in the Canadian Highlands, and the phe­ cut down'through the lake beds and swung east and west, forming the beautiful terraces which comes a series that was once composed of clayey quieter off-shore area, and in the central zone of nomena of ice erosion and deposition are wide­ border the stream and make much of the charm beds with interposed limestone beds. The former this latter area, where the basin was widest, the spread. Before the expansion of the ice sheet have been changed into mica-schists and the still finer Chicopee shale was laid down. All the relief of the region was essentially what it is of the valley scenery. These terraces are the latter into thick strata of hornblende-schist. these deposits are partly contemporaneous sedi­ now, but the rocks were deeply decayed and sites of many of the most attractive towns along ments, differing as the strength of the current and buried beneath clay and partly decomposed min­ the river. As the river has swung to and fro, it CARBONIFEROUS PERIOD. the character of the shore rocks affected them. erals. This layer the ice ground off and carried has built up the broad, rich meadows which make the best farming land of the district. There are no sedimentary rocks of Carbon­ Strong tides, like those of the Bay of Fundy, forward, distributing it as a peculiar The great deltas of Mill and Chicopee rivers iferous date known in western Massachusetts, seem to have swept up the west side of the bay, stiff clay, or hardpan, containing a heter- beneath5 the had reached clear across the lake, so that although they occur in the eastern part carrying the material of the granitic shore rocks ogeneous variety of bowlders. Such a when the lake gave place to the river the lat­ of the State about Narragansett Bay far north, to rest against a shore made of the deposit, characteristically developed only under T-TT T/» TIT boniferous ter could not regain its pre-glacial bed, which and near Worcester. It such beds age not dark schists, and the return currents ran along glaciers, is called till. Till extends as a thick ^ present. is far east of and much lower than its present were deposited here they have been the east shore, carrying the eastern shorewash sheet very generally covering the rocks of all the one. It therefore soon cut through the lake beds entirely removed by erosion. It is more probable south, while quieter waters and shifting currents region of western Massachusetts. This deposit and came to the rock. Thus the waterfalls at that the region had been raised above sea after spread the sediments in the central area. often thickens into very regular hills, which are Turners Falls and Holyoke were formed and the the deposition of the Bernardston Devonian for­ The accumulation of sediments was interrupted elongate in the direction of the motion of the ice. water power of the river was concentrated at mation, and formed part of the extensive Carbon­ by an eruption of lava through a fissure in the They are called drumlins, or locally " hogbacks." these points. This has determined the sites of iferous continent. earth's crust, which opened along the bottom of They are marked features of the landscape in the In tracing the history of the Paleozoic age from the basin. The lava flowed east and west on the valley, especially near Northfield and Northamp­ the largest industries in the valley. Holyoke 3. DESCRIPTION OF THE HOLYOKE QUADRANGLE.

GEOGRAPHY. the west while the river cuts through the mid­ Connecticut Basin just beyond the limits of the along the eastern border of this hornblendic band. dle of the sandstone hills. quadrangle on the east, and its great sheets can be The band crosses the area from north to south, General relations. The quadrangle represented The trap ranges on the south are isolated by seen on any of the western roads of Pelham or inclosed between sericite-schists on either side, by the Holyoke atlas sheet is bounded by the exactly similar depressions the narrow gorge of Shutesbury, dipping westward toward the valley, and standing always nearly vertical. Details of parallels of 42°-and 42° 30' and the the Belchertown ponds on the east, beyond this but the rock is not present at the surface in this its distribution and mineral associations are as meridians,. 72°i_ 30' and 73°.i_ ItT embracesi Extent. quadrangle, and the broad depression followed quadrangle except in Granville, Tolland, and follows: therefore, a quarter of a square degree of the through Easthampton by the Canal Railroad on adjoining towns in Connecticut. These sheets The band is narrow where it enters the quadrangle from earth's surface, measuring 34.51 miles from north the west while here again the river cuts through resume this westward dip and, extending under the north; It is locally changed to soapstone on the river to south and 25.64 miles from east to west, and the trap range at its center. the area to the west, form the platform upon road in Windsor, and carries a great bed of serpentine and soapstone and some emery at H. Smith's in Middlefield. Two containing about 884.85 square miles. It extends Across Amherst and Northampton the rounded which all -the younger rocks rest and come up to miles south it widens suddenly to 200 rods, and much the two-thirds the distance across the State Pontica, hills of glacial stony clays called drumlins, or in form the crest of the Berkshire Hills along the larger half on the east becomes serpentine, derived largely homely phrase "hogbacks," form an important western edge of the plateau in Peru. from the hornblende-schist and retaining its structure, but of Massachusetts from its southern Ssi0nntsand possibly partly derived from an olivine or olivine-enstatite boundary, covering the greater portion quadrangles< element in the scenery. Finally, the winding SILURIAN. rock. This serpentine continues more than a mile, to the bed of Hampshire and Hampden counties and going Connecticut, with its many bends and oxbows, of the Westfield River, on the south bank of which the rock changes back suddenly to hornblende-schist, and continues, over on the north into Franklin County and on the and the rich bottom lands or meadows in Hadley, Hoosac schist. The distinction between the with the above width, several miles to the south, making the south into Connecticut. At its northwest corner Hatfield, and Northampton, form an appropriate albitic mica-schist (Hoosac schist) and the seri- mass of Gobble and Round Top mountains. Fine pseudo- it touches Berkshire County. The adjacent fifteen center and foreground of a region as varied in cite-schist (Rowe schist), which is so Feld8 athic morphs in serpentine were formerly found in the serpentine marked in the northern and central mica-schlst- north of the river, and were supposed to be flattened quartz minute quadrangles are, on the north the Hawley beauty as it is diversified in geological interest. crystals. They prove on measurement to be olivine. and Greenfield, on the east the Belchertown and Next southwest is the Southampton-Westfield part of the State, fades out gradually in the In the river, opposite the railroad bridge at the west line of Chester, the north end of the remarkable emery vein is Palmer, on the south the Hartford and Granby, plain, underlain by sandstones and leveled up by southern part of this quadrangle, both beds losing beautifully exposed, and it continues to border the horn­ and on the west the Sandisfield and Becket. sands which were deposited after the some of the characteristics which separate them blende-schist on the east for a distance of 3 miles. / retreat of glaciers that once occupied field sand" farther north. The small porphyritic albites of Steatite (soapstone) appears on the east of the bed in Gob­ TOPOGRAPHY. TT Plain- ble Mountain, and both steatite and serpentine occupy the the area. Upon this plain the streams the former gradually become inconspicuous, and same position in the old mine. The emery is disseminated in Two distinct topographic types are represented run north and south from a low divide, which is the feldspathic constituent comes to be mainly magnetite, and the bed reaches in places a thickness of 16 feet and is estimated to average 4 feet. on this sheet, an upland and a valley. The upland not marked at all in the topography. The great potash feldspar, apparently as a result of granitic A great number of beautiful and rare miner­ is the larger, western part, and it varies The western mass of Mount Tom dominates the valley, and the impregnation, as granite becomes abundant and als accompany the emery, and in the list below c^m pally inCg in general altitude from 1200 to 2000 upland- trap ridge of which it is a part is continued south­ appears in large masses. The Hoosac schist is they are arranged in the order of their age : the emery- Stage 1. Magnetite, emery, corundophilite, bordering an feet above the sea. The summits of most of its ward at a lower level. The ridge is deeply generally a coarse muscovite-biotite-schist, show­ olivine-enstatite rock. notched at several points, and each notch corre­ ing on foliation faces broad plates of muscovite hills, and many broad flat areas which rise grad­ Stage 2. Corundophilite (in veins in magnetite), tourmaline, ually higher toward the northwest, represent an sponds to a break, or fault, in the rocks. It rises and biotite regularly intergrown and containing pyrite, epidote, corundum (white and blue in veins), and oligoclase. ancient plain, which sloped southeastward from to considerable elevation in Proven Mountain, often garnet, staurolite, and gray cyanite. Toward 2a. Corundophilite (in incrusting layers on Stage 2), margarite, diaspore, rutile, epidote, chalcopyritei the Housatonic River toward the Connecticut and has always a sharp western and a more the base is a peculiar rock. In a limpid granular calcite, menaccanite. Valley. This ancient plain, which is otherwise gradual eastern slope. This range bounds' the quartz mass, distinct scales of silvery muscovite, %b. Menaccanite, margarite, diaspore, brookite, calcite. well preserved, is now deeply notched by the Westfield plain on the east. red biotite, and pyrite are compressed into paral­ Stage 3. Specular iron, aragonite, pyrite, chalcopyrite. 3a, Calcite, malachite. picturesque transverse valley of the Westfield The country east of this ridge may be divided lelism, producing a bright silvery luster. It con­ Stage 4. Corundophilite altered to amesite, margarite, and River and by the wild gorge of the Westfield into two portions. That west of the Connecticut tains much plagioclase. This is a part of the diaspore bleached. The enstatite rock changed Little River. On the south the tributaries of the and north of the Westfield River is an undulating Hoosac schist, but is an inconstant bed. Rarely to serpentine, and this to talc. Farmington River drain the area by longitudinal area of red sandstone and glacial clay. That hornblende-schist beds and a pale-green actinolite- In North Blandford is a great development of steatite which garnet rock derived from limestone occur, seems to have been derived from a coarse radiated actinolite, valleys. Farther north a watershed running south of the Westfield and the larger area east of and near this an extensive bed of serpentine containing much north 2 or 3 miles from the east border of the the Connecticut form part of a flat sand plain, the By the development of three folds in these chromite and a trace of nickel, probably derived from an bottom of an ancient lake, broken rarely by a reef schists, two of which bring the Becket gneiss to olivine rock. On the old maps this locality is called the plateau separates the streams that run directly Crater. into the Connecticut from the many branches of of trap or a drumlin, and extending east beyond the surface, and by the pinching out of the over­ Farther south in Blandford, at the Osburn soapstone the Westfield River. The southeastward slope of the limit of the quadrangle to the foot of the lying hornblende-schists between these folds, the quarry, is a thick bed of black enstatite-serpentine with Wilbraham Hills. The Connecticut River and Hoosac schists come to occupy a broad area in the much soapstone, derived from a coarse radiated actinolite, the ancient plain controls in the main the direction itself derived from the enstatite. of the streams, though the East Branch of the its tributaries have cut deep trenches in these southern portion of the quadrangle. At the bottom of the brook gorge to the west of the quarry Westfield flows south across the towns of Goshen sands, forming the meadows which border the Rowe schist. This formation barely skirts this is a remarkable serpentine derived from a coarse pyroxenite. The pyroxene can be traced in the change into actinolite, and Chesterfield, following the trend of the rock streams and the fine terrace scarps which flank quadrangle on the west, and is best exposed on and this into serpentine and talc. Farther south, in Liberty bands. South of Shack Street in Chesterfield this them. the road going west from Chester, at the second Hill, "West Granville, the amphibolite band widens greatly, bridge. The Rowe schist north of North Bland- and, sending off a long spur to the south, bends sharply and brook turns sharply west; at a point from which turns north for 3 miles ; then turning abruptly south again, it seems formerly to have run southeast into GENERAL GEOLOGY. ford is a barren sericite-schist of pale- Qreen it extends to a point south of the cemetery in East Granville. green color, often spotted with chlorite Site0-86 Here it again bends north and runs 8 miles northeast to North Branch of Manhan River, and so directly SEDIMENTARY ROCKS. Atwater's serpentine quarry in Russell. Thence it runs south into the Connecticut. It appears to have been plates, quartzose, and greasy to the feel, schlst' again for some distance, to disappear below the sands of the diverted into the Westfield River by a tributary The rocks occurring in the Holyoke quadrangle but in the vicinity of Blair Pond it becomes also valley, south of Munn Brook in Southwiek. At the cemetery feldspathic and more coarsely crystalline, and in East Granville a remarkable change takes place in the bed. which cut back from the deeper valley. consist of: 1. The very old crystalline schists of The amphibolite becomes quite subordinate and the series is Among the summits which rise above the gen­ the western plateau, which are assigned Geological loses its tendency to hydration, apparently from represented by great beds of black serpentine of a very to the Algonkian, Cambrian, and Silur- *«»><»visions. the influence of the granite. South of North peculiar structure. It is made up often of large interlaced eral level of the ancient plain are High Ridge and prisms, formerly enstatite, and still showing at times a core Merritt Hill in Williamsburg, and More Hill in ian systems. These schists are penetrated by Blandford the rocks are wholly covered for a of this mineral surrounded by bastite. More often these Goshen, all of resistant granite; and farther west great stocks and dikes of acid intrusives. 2. The long distance. The boundary is drawn so as to prisms are completely altered to a black serpentine. The let the Rowe schist taper to a point, and farther interstices between these prisms are usually filled with a Gobble Mountain and Round Top, in Chester, much later Juratrias sandstones, conglomerates, transparent dolomite, the solution of which gives the rock a composed of hornblende-schist, are conspicuous and basic intrusives of the Connecticut Basin. south the distinction between the Rowe and the peculiar ragged surface. This is best studied east of H. 3. The relatively modern surface deposits of Hoosac schists is not carried out. Cooley's, in a pasture a mile southeast of Sweetman Moun­ landmarks. A deep depression has been eroded tain, where the prisms of enstatite are sometimes a foot long ; in the upland in Goshen and Chesterfield towns, Glacial and post-Glacial age. A series of rocks which seems to represent the or east of J. Downey's in East Granville, where the bed over a circular area of softer rocks. whole Silurian succession west of the river, but in graduates into a nephrite-like treinolite -schist, and that into ALGONKIAN. simpler form and with less thickness of individual a great bed of white granular limestone ; or at Atwater's, at The western upland or plateau ends with an the northern elbow of the band, where the enstatite remains exceptionally steep descent to the low sand- Washington gneiss. A band of ancient gneiss beds, extends west from the gneiss of Pelham and only in the green foliated bastite found in the multitude of covered plain which extends east _ enters the quadrangle at its southwest corner and occupies the narrow bottom of the valley from the great bowlders scattered over Granville and Southwiek. The j- The Connect!- most important place for the study of this band is the newly beyond the limits of the quadrangle. cut Valley- runs up across Tolland, narrowing to a Dark mica_ pointJL where the railroad crosses Locks _East . of_.. the opened quarry of the Hampden Marble Company. South of This escarpment, which runs from longitude 72° point near Black Pond. It is distin- Kiitf"*1 Pond Brook south past Leverett Cen- Juratrlas- Little River, on the Westfield-Russell line, the bed is 150 feet ter. The series goes beneath Mount Toby, and thick in cyanite-bearing mica-schist and is cut by granite. 40' on the north to 72° 50' on the south, forms the guished by its highly micaceous and gneiss' The western third is enstatite-serpentine. The remainder is western boundary of the Connecticut River Basin. fibrolitic character. Its beds dip on either side south of the mountain extends west to underlie a doloinitic marble, shot through with long serpentinized beneath the white Cambrian gneiss. Just beyond Amherst and Hadley. It is so greatly faulted enstatites in beautiful stellate arrangement. The section of this basin in the vicinity of Traces of the presence of enstatite appear in the serpentine Northampton and Amherst covers the TheNorth. the quadrangle in Riverton, it includes a large bed and crushed and impregnated with granite that at Hubbard Brook just over the State line and at Osburn's most picturesque portion of the Con- t^nofthT" of limestone containing chondrodite, and to the its mapping has been very difficult. quarry. "Whenever this occurs the rock was probably once enstatite or enstatite-olivine rock. Yet the only certain necticut Valley and of the State. The valley' west the gneiss grades into the blue quartz-gneiss The basal bed of the series, resting upon the proof of the presence of olivine found in following this band broad and beautiful meadows bordering the river so common in this formation. Cambrian biotite-gneiss of Pelham, is an altered across the State was the occurrence of olivine pseudomorphs are bounded on the north by table mountains of conglomerate, now a feldspathic mica-schist or a in the serpentine in Middlefield, which have been described CAMBRIAN. as quartz pseudomorphs. sandstone and conglomerate the Sugar Loafs gneiss with black and white mica, which may be Northward from Munn Brook, then, all the serpentine and Mount Toby and walled on the south by Becket gneiss. A broad band of light-gray, correlated with the Rowe schist. Its description beds are enstatite-serpentines to Osburn's quarry, where the eastern bed and the steatite have this origin ; the western is the trap bluffs of the Holyoke and Mount Tom friable biotite-gneiss surrounds the Washington is based wholly upon the beds in Northfield a pyroxenite-serpentine. In North Blandford the somewhat ranges. The granite mountains which make the gneiss last described, and dips out Mountain, in the Warwick quadrangle, and it peculiar "Crater" serpentine is probably derived from an eastern rim of the uplands overlook the meadows from it beneath the newer rocks. It frifbieTio-' touches only the extreme northeast corner of this olivine rock. The soapstone, like that at Osburn's, may have -..-11 -IIT tite-gneiss. been derived from an enstatite rock through actinolite. from the west and form the western border of is thin bedded, and the thick-bedded quadrangle as it passes from Locks Pond Brook the Connecticut Valley, in the wider topographic granitoid gneiss, like the fine quarry stone in to the west entrance of Rattlesnake Gutter in the k In earlier publications the Chester amphibolite sense, while beyond the limit of the quadrangle Becket, does not appear here. In places it is-some­ Belchertown quadrangle, next east of this. band was described as being composed of altered the gneiss ridges of Pelham shut it in on the east. what rusty and contains large garnets, becoming Chester amphibolite. By far the most interest­ eruptives. In Monograph XXIX, on The sandstone hills which form the northern much like the f eld spathic schist above, so that in ing series within this quadrangle is the the Geology of Old Hampshire County, - »i 11 -i i f i M Hornblende- band of hornblende-schist (ampnib- schist, in boundary are separated from the crystalline rocks the next quadrangle south the distinction between v -L part replaced later discoveries have led me to present on either side by deep depressions the Leverett the two is hard to trace in the field. olite) and soapstone beds mapped as t&farndn~ the view that the band is an altered stone' gorge, occupied by the New London Railroad, on The gneiss of Pelham, so commonly used as a the Chester amphibolite. The unique soapstone- limestone or dolomite, possibly contemporaneous the east, and the low plain of South Deerfield on building stone, forms the eastern border of the magnetite and emery bed at Chester is situated with the Bellowspipe limestone in western Berk- shire. The first view was based on the fact that distinguished is the smaller quantity of graphite and other In the northern part of the quadrangle the rock extends accessories. The distinction is here comparatively unimport­ CARBONIFEROUS. from the Connecticut River westward, including the isolated many amphibolites are altered eruptives and that ant, and is carried out partly for the sake of uniformity with area in Amherst village, and farther south occupies the whole enstatite is commonly an eruptive mineral and adjoining sheets and partly because in the great mass of these As has been stated on an earlier page, there are width of the plain west of the Holyoke Range. It is syn­ emery a possible contact mineral. The finding of graphitic schists any distinction is important in unraveling no sedimentary rocks of Carboniferous age known chronous with the Mount Toby conglomerate, which is the the structure and expressing it on the map. eastern shore deposit, now raised between two great faults great beds of dolomitic limestone in the series in this part of the State. A description of erup­ above its former level. Its western limit is along the foot of and the passage of these limestones into enstatite Conway schist. -A large portion of the quad­ tive granites of Carboniferous age occurring in the bluffs, where it seems to meet them by a nearly continuous series of faults across the State; but the junction is deeply limestones, the fact that the Naxas emery is found rangle is covered by this formation, which is also this quadrangle may be found under the heading covered by the terrace sands, so that the coarsest western in limestone and that many amphibolites are very extensive northward beyond its limits. The "Igneous rocks." shore deposits are mostly concealed. Just south of Whately derived from limestones, together with the great finely corrugated muscovite-schist, which is the village, near the western border, it becomes a coarse granitic JURATRTAS.* conglomerate, which represents a part of the western shore extent of the series as it passes across Connecticut, principal rock, is often so contorted that no strike bed. It is also a decided conglomerate at Mount Tom station Massachusetts, and Vermont, lead me now to can be made out. It is dark from the abundance The map shows that the Juratrias red sand­ in the center of the basin and just beneath the Holyoke trap, believe it to have been mainly a calcareous sedi­ and it may have been brought up here by faulting. of coaly matter; small garnets and staurolites stones enter the quadrangle from the north with a The low ground of the Westfield-Southwick plain is under­ mentary formation, with possibly some very basic are usually abundant in it, but they grow rare width of about 8 miles, are greatly con­ lain by this formation, which is there a coarse feldspathic eruptives associated therewith. It was a broad to the north; and zoisite and blue cyanite are stricted where they pass west of Mount SXtSi red sandstone, whose material has been largely derived from the granites of the hills to the west. Along the western border band of limestone, and waters leaching through common. Warner, and expand toward the south. sandstone- it becomes a granitic conglomerate. Its red or buff color the superincumbent schists deposited a great bed The rock is generally spangled with many small, This narrow zone in Hatfield is due to extensive comes from the iron rust, which forms a large part of the of limonite and gibbsite on it, like the West elongate, shining, black rnica scales, set trans­ erosion, which has worn away the sandstones cement by which the ancient gravels were solidified. Stockbridge ores on the Stockbridge limestone. versely ( to the foliation. There are down to the schists and left a sheltered remnant Mica-schist, Longmeadow sandstone. The Longmeadow This was then altered to the magnetite-emery bed, many beds- -i olr. a sandyi quartzite, , with ,' , of sandstone isolated in the village of Amherst. sandstone represents an oifshore facies of the while the rusty dolomites changed into enstatite- small scales of red mica regularly This erosion was aided in exposing the crystalline sediment spread over the bottom of the disseminated. These make excellent blende=sch*t- limestone and amphibolite. rocks by the irregular surface of the latter and by Juratrias bay. South of Titans Pier, Savoy schist. This broad formation is, in its scythestones. Beds of a black limestone full of faulting, which has raised the eastern portion of where the Holyoke trap projects into fn 0an"maig passage across the quadrangle, a very nodules of graphite and dark mica appear north the basin and depressed the western portion. , . , ci i j» i tracks and tne river,' the coarse ouerarloaio arkose °tings.ner mark- monotonous mass of quartzose mica- or of the middle of the quadrangle, and increase in The eastern border of the sandstone was doubt­ with inter- grades into the buff or brown sand­ hydromica-schists, generally quite bar­ amphibolite. number northward. These beds are often changed less high up on the slope of the Pelham ridge, stones, which have been quarried on both sides ren of all accessories. above and below for 2 or 3 inches into hornblende- beyond the eastern border of the quadrangle. of the river in Larrabee's quarries. This is the In the central portion, about Chester, many amphibolite schist, and when blocks are separated from the The southern part of the quadrangle pre­ north end of a broad band which extends south beds are intercalated, and large garnets occur in highly mica­ ceous, coarse biotite beds, also beautiful hornblende in black ledge they weather in swampy places into forms sents a wide section of the "Connecticut River down the center of the broadened bay. It is a blades penetrating a white quarfczite. This facies of the for­ like plowshares, anvils, etc., from the solubility sandstone," as these beds have been called, quartzose brownstone, oftentimes somewhat feld­ mation is well exposed in the cuttings west of the Chester of the limestone. because of their typical character in the valley; spathic, and cemented mainly by iron oxide. It railroad station. Farther south this formation consists of a quartzose hydro- In the western portion the schist is very fine they are widely known among geologists on suffers the same superficial change as the preced­ mica-schist, more or less chloritic, often barren over large grained and of the type described above. In the account of the "bird tracks" which occur here in ing rock. It abounds in branching tubes of sand­ areas, frequently carrying much pyrite and garnet, the latter changed more or less into chlorite. Its vertical beds present eastern portion it is greatly cut by large masses abundance and beauty unequaled elsewhere, and stone about the size of a pencil or smaller, which a very monotonous aspect. of granite and becomes itself coarser grained, they have been fully described by President are of the same material as the rock itself, but Beds of black hornblende-schist are not infrequent around barren of all accessories mentioned above and Edward Hitchcock, in a magnificent work pub­ separate easily from the rest of the rock. They North Blandford, but as the Savoy schist widens to the east in a broad anticline, this becomes less common and the rock much impregnated with quartz and pegmatite lished by the State of Massachusetts. have been thought to be the remains of seaweeds is cut by great granite masses and loses the greasy feel of veins. It is a rather coarse muscovite- or mus- The steep walls of the valley, the series of and have been called fucoids, but they are 'ferru­ hydromica. In the northeast corner of the quadrangle the Savoy schist covite-biotite-schist, rendered dark by graph­ faults which bound it on each side, and the great ginous concretions. Many layers of the rock are is a micaceous quartzite, generally containing a green chloritic itic dust. The fine and regular corrugation thickness of the sandstones, or, what is The Con_ covered with the tracks of animals of every size, mineral, which is at times certainly derived from garnet. common farther west gives place to an irregular the same, the great depth of the basin Fe^s's'ibiy" ripple marks, mud cracks, raindrop impressions, Sometimes it may be called a whetstone-schist. It is exposed all along the road east of Mount Toby, beginning a little contortion, and the whole is greatly changed from in which these sandstones are gathered, anft valley' and a multitude of markings which have not been north of the railroad crossing, and in the cuttings of the rail­ the normal dark-spangled and corrugated schist are best explained on the hypothesis that the explained but which prove that the waters were road and in the brooks coming down from the mountain just south of the Mount Toby station. In Roaring Brook the farther west by the intrusion of the granite. basin is a "graben," or rift valley, formed by the shallow and that the deposits were often laid bare Mount Toby conglomerate is seen resting upon it 50 feet above Tho thickest bed of limestone starts at Whately Glen and sinking of a great block of the crystalline sub­ by the tide. The valuable building stone of the the railroad. The rock was very greatly contorted and runs south across the town of Whately. Parallel to this runs stratum between faults. These faults have a region comes from exceptional beds in this series. crushed, and then cemented by quartz and hematite, and at a thick bed of hornblende-schist, and abuts against the great certain symmetry with the curved outcrops of the a later time jointed, so that it falls easily into small pieces. mass of granite which occupies so much of the quadrangle. Chicopee shale. This is a central band, which A bed of hornblende-schist crosses the northeast corner of Fragments of the three rocks, the mica-schist, the limestone, Holyoke and Greenfield trap sheets, projecting on begins at Holyoke and is best exposed along the the quadrangle, south of the great mass of granite which lies and the hornblende-schist, can be found for many miles south the east into their concavities and on the west railroad cutting near the Holyoke dam, west of the road extending north from Leverett Center, and included in the granite in the line of their strike and in " ed a second broad strip of hornblende-schist stretches southwest parallel positions. This fact proves that these rocks once preserving a marked parallelism with the lobes where it is a thin dark-gray shale or from A. Field's on the road to Leverett Center west of the extended together across the granite and have been removed of the trap. shaly sandstone, coaly, and showing £a,|altcrys= railroad. It is often biotitic, and is generally a thin fissile by erosion. The granite is largely hornblendic in the area of Mount Toby conglomerate. The Mount Toby rock, stretched by pressure It has a dark-green color, and the hornblende-schist, biotitic in the area of the biotite-liine- many minute impressions on the laminae, is made up of quartz, hornblende, feldspar, and magnetite. stone, and muscovitic in the part covered by the muscovite- conglomerate is composed of coarse materials some of which have been formed from salt and Hawley schist. This formation runs south schists This indicates that the granite melted up into the varying; from pebbles 2 inches in length gypsum crystals which have been dissolved out. schists, and incorporated much of them into its mass. -.IT r> - Coarse con- across the northern half of the quadrangle, with to masses with dimensions 01 ironi argillite,glomerate of The beds appear at the mouth of the Chicopee southerly strike and nearly vertical dip, and in Amherst feldspathic mica-schist. The equiva­ 2 to 4 feet. The rock is very largely, ^chSt'and River, and in the bed of the Connecticut River at Chester is overlapped by the Goshen schist. It is lent of the Conway schist on the east side of the and often wholly, made up of com- veinquartz- Mittineague, where the rock consists of red shales exposed also in an oval area around Burnell Pond river is the Amherst feldspathic mica-schist, minuted argillites, quartz-schist, and vein quartz, with many nodules and narrow beds of concre­ by a dome-shaped uplift. It is a ferruginous for­ which is coarser and more ferruginous. Where with larger pebbles of the same material. In tionary limestone and casts of skeleton salt crys­ mation,' consisting;O of hornblende-schists^ Hornblende-, ., _, these schists are exposed in Mount Warner many cases, as along the eastern slope of Mount tals in calcite. It also appears in the beds of with soft chlorite- and sericite-schists. SJlfJSSr' and and across Amherst by the erosion of the Juratrias Toby and in Gill, rocks from 1 to 2 feet long are brooks in Agawam and Thompsonville, near the In the two latter rocks black hornblende schlsts* sandstone, they are cut in every direction by num­ set as closely as they can lie in a coarse gravel Connecticut, but the rock in place is so covered needles arranged in sheaves appear abundantly on berless dikes of coarse pegmatite, and are much from which all sand has been washed. A partial that it is not possible to draw a boundary for it the slabs, whence is derived the name, fasciculite- more metamorphosed than those west of the river. arrangement of the pebbles with their flat surfaces with accuracy. schists. The schists are impregnated with granitic material parallel to a common plane and the rude stratifi­ Grranby tuff. This consists of heavy-bedded The whole slope on the eastern side of the val­ from the pegmatite, and thus become cation in the coarser and the finer beds is -the black tuff and tuffaceous sandstones varying ley that separates Middlefield and Worthington is only structure. feldspathic. Fibrolite is a rather com- from fine-grained° ( volcanic sandstones Black_, , mas- occupied by these rocks, with a width of about a mon constituent,... , Tlinking; i them,1 with ,! j-ithe withimpregnated granitic to coarse breccias and agglomerates; Sarsevoi?d 7 o material. In the bed of Roaring Brook, and of the next brook to the third of a mile. The rocks abound in large gar­ Brimfield schists of Worcester County. north on the east flank of Mount Toby, about 50 feet from rocks made up wholly of volcanic nets, superficially changed into chlorite, which They form a disturbed syncline in Mount Warner above the level of the New London Northern Railroad, the debris to such as contain abundant fragments of conglomerate can be seen resting upon the contorted quartz- with the fasciculite form fine cabinet specimens. and extend east across Amherst, dipping west ites. As we go westward from this point the whole mass of granitic and gneissoid rocks. The finer-grained Goshen schist. This formation includes the that is, away from the lower portion of the series the main ridge of Mount Toby is found to be made of this varieties contain the materials of granite, espe­ lower portion of the Calciferous mica-schist of coarse rock, but following any of the " sugar roads " into the along 'the eastern border of the quadrangle. mountain from the western side we find several bands of the cially white mica, on the lamination faces, and Hitchcock. It is almost wholly free Leyden argillite. Back of Whately village is Longmeadow sandstone, which penetrate the horizontal beds grains of quartz in the mass of the rock. from limestone and is a dark-pray £r«fspcov!te= a most interesting band of extremely fine-grained of the coarser rock and thin out tinder the main ridge. These The roadside a mile or two south of Smith Ferry and the , ... ., , . , , ° ' J schist. indicate successive oscillations of level, during which the graphitic muscovite-schist, olten arena­ mica-schist or phyllite, almost too Ver f.ne railroad cuts adjacent furnish fine outcrops of this bed, and finer-grained sandstone extended east across the conglom­ enable one to study it near the center of eruption and dis­ ceous and splitting into flags 2 to 3 inches thick, coarsely crystalline to receive the name 23JKftrlnlc"" erate several times and then gave place to the coarser material tribution. which are much used in the large towns in the of argillite, by which it has usually phyllite- again. The great angular blocks of diabase a mile north of Smith Connecticut Valley for sidewalks. It is abun­ been known. It is greatly corrugated, and this Sugarloaf arJcose. This rock, which is a coarse, Ferry, by the cemetery, can be seen to have fallen into and to have bent down the layers of the mud, now turned to dantly crowded with small red garnets, especially structure is brought out by distinct sandy layers. buff to pale-red sandstone, and which often sandstone. The blocks grow gradually smaller southward, where micaceous, and spangled with small shining It is often perfectly cleaved, as a result of pres­ becomes so coarse that it can be called _ and above Larrabee's quarry on the north line of Holyoke a Coarse sand= few scattered fragments of trap, an inch or two long, in the black mica plates set across the bedding where sure, and this structure expresses itself by a part­ a fine conglomerate, is made up largely feldspathic sandstone are all that remain. More easterly, on it is more arenaceous. Staurolite is generally ing which separates the rock into thin parallel of the debris of the granite and coarse the road going south from The Notch, at a small brook, the rare in the central portion of the quadrangle, and plates. Many irregular veins of white quartz pegmatite veins of the high ground to the west. cross section of the bed is very instructive. Here the frag­ ments are from half an inch to an inch in size. The transi­ is wanting in the northern part. cut the rocks where the road crosses the brook The flesh-colored cleavage pieces of the feldspar tion from the tuff to the feldspathic sandstone above and The typical region is that surrounding the oval of Hawley west of WThately, and the limestone of the Conway and the shining scales of white mica give char­ below is very sudden. The tuff itself is deep brown from rust. schist in Goshen, and dipping out from it in all directions, acter to the rock. At the surface it is generally In tracing the outcrop, one finds portions of it wanting, A band identical in lithological character and of the same schist appears beneath it, showing that the argil­ apparently faulted out of sight; and on the other hand, thickness crosses the western portion of Worthington. In lite is newer than the Conway schist. Along its softened by the solution of the cement and often portions of it are found far beyond these limits, having been Goshen occur bands of light-gray biotite-gneiss, with massive contact with the tonalite it is greatly altered by spotted green by the reduction of the iron rust let down from above during the time of faulting, and now texture and fine grain, which resembles the Cambrian gneiss, being exposed by the great erosion which the sandstone has but under the microscope proves to be much more like the the latter into a greenish gneiss, and farther out­ by decomposing organic matter. This process is suffered. schists with which it is associated. ward into a chiastolite-schist. These chiastolites in places carried so far that the surface is white The striking cases of this kind are: (1) In the bluff over­ The schists run across the southern half of the quadrangle from the leaching out of the reduced iron salts, looking the Middle Belchertown Pond, and (2) a mile and a in a narrow band, and are well exposed at Salmon Falls are further altered, while retaining the black cross quarter north of the cemetery in Granby and a mile east of (Fairfield), where their thickness, much diminished from that in section, into a mass of muscovite scales in thus showing the kaolin resulting from the decom­ The Notch, and thus far up the mountain side and far north seen farther north, can be clearly determined. In the rest of which minute staurolites in twin crystals are position of the feldspar. of the present outcrop of the bed. Here a mass projects from the area this is not so clear, as, being caught up in the broad the ground and is shaped like the rude model of a great tele­ anticline, the rock is about as much corrugated as the next embedded, and the latter are superficially changed * See paper on the Triassic of Massachusetts, by the writer: scope on its stone pedestal. This shows that the tuff extended formation above, and the only criterion by which it can be into a fibrous mineral. . Bull. Geol. Soc. Am., Vol. II, p. 451, 1891. far north and east of its present outcrop. Holyoke 5. IGNEOUS ROOKS. the upper surface of the bed and the western If the sandstones were removed from beneath, the trap valley was persistent and long continued. The would stand like a great toadstool, the core being its stem and CABBONIFEROUS. slope coincides with the columnar structure, which the top being broken away on the west and south. If the upland area presents few points of special interest is at right angles to the surface of the bed, it runs portion of this top which extends in an easterly direction be in respect to glacial accumulations. ERUPTIVE MASSES. in a bold hill with precipitous western face, as in followed a half mile southeast to the steep hill just north of Larrabee's quarry by the railroad, the sheet is seen to rest on Over Ashfield and Plainfield and the depressed area in Goshen WilUamstown granite, Belchertown tonalite, and Mount Tom and Proven Mountain. Where ero­ the sandstone, which is baked. Just south, in the quarry, at the till is especially thick. A marked bowlder train of the Middlefield granitite. The granitic igneous rocks sion has worn off the trap sheet more nearly hori­ a much lower level, the trap appears in mass beneath the porphyritic granite occurring in place near sandstone and tuff. The sheet is covered by a tuff bed Middlefield, extends southeast across Chester, A marked which were erupted in Massachusetts about the zontally the ridge is less elevated, but the trap throughout its length from Smith Ferry, and the mass in the the rock being easily identified by its peculiar train. close of the Carboniferous period occur on both covers a broader surface. quarry lying beneath the same tuff is doubtless the same character. When first discovered the emery bed To the north, in Sunderland and Deerfield, a bed sheet. A fault of about 100 feet downthrow has caused the on top of Round Top was finely ice-polished. The main val­ sides of the Connecticut Valley, and their distri­ difference in level. This trap in the brook bed just north is leys all run with the former direction of the ice. They are bution in this quadrangle is very interesting. The of trap similar to the main Holyoke sheet rests on amygdaloidal at its surface and the sandstone rests normally overlarge for the present streams occupying them, but only central core is the great block of tonalite or horn- the Mount Toby conglomerate, extends north­ upon it, but in the quarry the sandstone rests upon an exceed­ narrow gravel flats border them. On Mores Brook above ingly irregular surface of the scoriaceous trap, and the sand Searsville great delta-like accumulations of sand occur at blende-biotite-plagioclase rock in Hatfield which west across the river on the Sugarloaf arkose, and was manifestly carried out over the still melted trap, since the several points where the valley widens suddenly, but these is mapped as the Belchertown tonalite. The stretches north far beyond the limits of the quad­ two are kneaded together in a very irregular way. The sand seem to have been formed rather by the dropping of its sand rangle. Slightly inclined to the east, its mass extends down in long filaments and disconnected shreds into by the overloaded stream as it expanded in the widened val­ High Ridge dome of granite, the Mount Pomeroy the trap for 1 or 2 feet, and small fragments of the trap ley than by ice obstruction forming a glacial lake. and Mount Tekoa masses, and a string of smaller forms the core of Deerfield Mountain just beyond are in other places included in the sandstone above. This All the settled portions of Amherst and Northampton are batholiths lie west of the tonalite. They are great the border of the quadrangle, and seems formerly sandstone shows abundantly the influence of the heated trap. underlain by till, and the difficulties of drainage, wet cellars, It is very ferruginous, and is for a foot or two above the trap and bad roads are largely due to this fact. The road north of and monotonous stocks of biotite-musco- Biotite- to have capped South Sugar Loaf and North made up of small flattened concretions. All its fissures for College Hall in Amherst and in front of the Forbes Library in vite-granite, occasionally carrying black granitemuscovlte = Sugar Loaf. This is apparently the reason why several feet up are coated with broad sheets of the finest drusy Northampton are illustrations. The till is a tough clay, often masses. they still retain a mesa form. The rock is a specular iron, in coarse crystalline plates, and large cavities requiring blasting in deep digging, so compact that it will tourmaline. Whatever masses may both in the trap and in the sandstone are filled with calcite in sometimes trim into specimens with conchoidal fracture like occur to the east are to a great extent hidden by dark, fine-grained trap, full of steam holes and crystals of considerable size. The most remarkable mineral porphyry. the later Juratrias rocks. In a bordering band thoroughly rotted where it occurs in the con­ found here is anhydrite, which occurs in large, bluish-white, finely crystallized masses, coarsely interesting In the valley near either side the hardpan is about 3 miles wide, west of the great domes, glomerate, dark and compact in the arkose. The foliated -,.,-, and-, slightly,. , j, radiate,,. , exactly,, resembling-IT theminerals trap. in smaller but considerable stocks of similar granite bed shows a superficial and two intermediate the Chesterfield cleavelandite. It is found in molded into great trains of drumlins, which are are abundant. Farther west comes a bordering sheets full of steam holes, indicating three imme­ masses as large as one's fist inclosed in the trap a foot or two wanting in the central portion. Castor below its surface. It was formed by the action of sulphuric and Pollux at South Amherst are fine raS|emen"t area, stretching from Granville north diately successive flows. acid, derived from pyrite in the trap, upon calcite, which is . , . no, ofdrumlins. typical specimens, as well as Sunset to Cummington, and beyond to North- Where the Holyoke Branch Railroad first touches the main found in the same cavities as the anhydrite. Y» 1 -i ,1 , l . p quartz veins. Hill and Round Hill in Northampton. Extensive field, that has numerous veins ot coarse trap sheet at the south end of Ashley Pond, a cutting exposes INTRUSIVE DIABASES. pegmatite which carry subordinate veins abound­ the upper surface of the trap, which is full of layers of sand are found inclosed in the till, small fragments of a compact, dove-colored inclusions of Blackrock diabase. Parallel with the Holyoke ing in spodumene, colored tourmalines, cleave- limestone.T i *x. Thesemi are frequentlyj. J.T angular,i buti _L thelimestone trap; in formed probably by sub-glacial streams, and, when landite, cassiterite, zircon, uranite, triphylite, they are also often so kneaded up with the trap ""thlbe'd"8 Range and about a mile southeast of it is a line frozen, blocks or even broad sheets of this sand as to give the impression that both must have ' , of volcanic cores, rounded masses of were moved along with the rest of the material beryl, etc. Beyond this is a series of great quartz been plastic when they were thus mixed. The trap is full of veins, often quarried for crushing. Outside of rounded holes filled with clayey limestone. With the micro­ various sizes filling probably the throats ancfent* beneath the ice. of ancient volcanoes removed by ero- volcanoes- this area, to the west, the country is for a long way scope the material can be seen to have flowed as a fine calca­ Such a layer extends 12 to 20 feet below the surface from the reous mud into the steam holes which open on the surface of sion. One of these plugs, north of Moody Cor­ Agricultural College grounds in Amherst south beneath Pros­ free from intrusive rocks, until near the western the trap fragments. In other cases the drops of mud were pect street to the Central Railroad cutting. It caused the border the unique Middlefield dike of peculiar inclosed in elongate swarms in the solid trap and seem to have ner, is a quartz-diabase. The others differ only unfailing wells of the region and the brook that ran formerly flowed with the liquid material. Other cavities are filled by a porphyritic biotite-epidote-granite appears. slightly from the bedded traps. They are fresher across the common. Amherst was formerly covered by great later infiltrated crystalline calcite. The broad surface of the and contain a little olivine. They baked the sand­ conglomerate bowlders from Mount Toby, and Northampton trap for 5 miles shows this structure. While the lava incased by granitic rocks from the north. Sunset Hill is still covered In Blandford, 3 miles west of Huntington village, at the in a thin solid layer was flowing over the bottom of the quarry above the Pontoosic Mills, is a remarkable pegmatite stones strongly and sent many dikes into the sur­ by them, except where cleared within the Asylum grounds. bay, heated waters rising from its surface caused convection In the south part of the district, except in Southampton, vein, 12 to 15 feet thick. A selvage of coarsest mica, 3 feet currents which swept the fine mud out onto the hot bed in rounding rocks. The larger of these masses resist. thick, is attached to the schist walls and is followed inwardly Holyoke, and West Springfield, the till or ground moraine of sheets which were then enveloped by still liquid trap where the erosion and stand out strongly as great domes. the ice is deeply buried beneath the post-glacial sands. A by two bands of feldspar crystals, well formed and 1 to 2 feet surface layer was broken up and were blended with the rest. across, mixed with the coarse mica, and this grades, by the Black Rock, south of Mount Holyoke, is a type, continuous series of large drumlins east of the main trap ridge All along the base of the trap sheet within the same limits the runs across Holyoke and West Springfield, and farther south disappearance of the feldspar, into a central smoky quartz same structures occur inverted, and are to be explained as and one well exposed for study. The core at the mass several feet thick. A similar vein of coarse pegmatite, across Agawam the larger drumlins rise out of the sands in a having been formed on the surface of the trap, as already Burnt Mill, a mile north of Smith Ferry, is well few cases, as in Liswell Hill and Buck Hill. wholly decomposed to kaolin and preserved from the erosion described, and then underrolled by its slow and continuous of the Glacial period, is now extensively worked near Bland- advance westward, and brought into a position at the base of dissected by the brook. Ice erosion. The broad, deep, sand-filled depres­ ford Center, for the finer kinds of brick and terra cotta. the bed. The scoriaceous structure in such great thickness SURFICIAL ROCKS. sion in the sandstones extending west along the and completeness, the fine brecciation, and the intimate mix­ JURATRIAS. ture with the limestone can have been effected only at the PLEISTOCENE. north foot of the Holyoke Range and continuing BEDDED DIABASES. surface. south along the western foot of the Mount Tom Beginning with the east end, the trap bakes the sandstone EPOCH OF GLACIAL OCCUPATION. Three great trap sheets were poured out upon on which it rests, as may be seen at the few places where the Range, is explained by the recoil of the ice as it the sea bottom while the Mount Toby conglom­ contact can be observed in the northwest shoulder of Mount Glacial sfaice. The area covered by this quad­ rose over the Holyoke Range, and by the south­ erate was gathering over the eastern border, the Norwottock, just north of the "Devils Garden," and a few feet rangle being one-half high plateau and one-half ward deflection of the ice as it impinged against north of Titans Piazza. From Titans Pier south to a point Sugarloaf arkose was forming over the broad bot­ near the Westfield River it does not bake the rocks on which lowland underlain by soft sandstone, the obstructing Mount Tom Range. In the same tom of the bay and in coarser varieties fringing it rests, but is amygdaloidal and kneaded full of limestone and these two sections being separated way a deep depression was caused in the sand­ and more or less brecciated. These structures, having been i i ! i ment. stone at the west foot of the Deerfield Mountain, the western border, and the Longmeadow sand­ formed on the surface of the lava stream and underrolled by by a very steep escarpment, while the stone was being deposited in the wider reaches of its advance, so that they come to lie on the bottom, have thus low ground is bisected by the sharp trap ridge, from Cheapside to South Deerfield. the bay. protected the underlying beds from the heat. the directions of ice movement, so far as they The depression is shallower where the range at the south Talcott diabase. The Talcott diabase is impor­ Hampden diabase. The Hampden diabase were controlled by topographic features, were end of Mount Tom. drops suddenly to a much lower level. This harmonizes with the explanation advanced as to the tant in its extension across Connecticut, but barely forms the strong foothill ridge east of the Mount very complicated and exceptional. The general cause of the depression. The sandstones occur high on the crosses the line into the Holyoke quadrangle. In Tom Range, which extends from a direction was S. 35° E. over the highlands and slopes of White Top Mountain and form a low watershed between the Manhan and Westfield rivers. Percival's account of the geology of Connecticut point south of Mount Nonatuck to the south over the valley plain, but the striae indi­ The Deerfield trap ridge has protected Mount Toby and the it was called the anterior sheet, as it lies in front south line of the quadrangle and beyond. Tom Range- cate that the ice was deflected more to the east Sugar Loafs from the ice attack. In the lee of the Holyoke- of the main or Holyoke sheet, which dips east and By Percival it was called the posterior sheet. At down the main branch of the Westfield River, and Mount Toin Range the sandstones are preserved 200 feet higher than to the west and north of the range, while between these faces west. the north end it is interrupted by an intrusive that the direction was almost due east down the ridges nearly all the sandstone has been removed in the lati­ Holyoke diabase. The Holyoke diabase is a dike, to be described later. The great tongue Westfield Little River and the brooks to the north tude of Amherst. typical diabase of monotonously uniform charac­ projecting east from the Blackrock boss on the and south of Granville and Russell. The move­ EPOCH OF GLACIAL RETREAT. ter. It is a dark-gray, very dense, fine-grained east side of the river may be its eastward pro­ ment was even a little north of east where deep Glacial lake deposits west of the Connecticut rock, with broad conchoidal fracture. Under the longation, but this seems to be an intrusive off­ gorges have that course. On the other hand, on Valley. The configuration of the upland west of microscope it is seen to consist of a network of shoot from the boss itself. The Hampden sheet the low flat valley bottom in Westfield opposite the Connecticut is such that over most of the area elongate triclinic feldspars inclosing shapeless can not be followed farther east. It is well these gorges, and up the side of the Mount Tom the glacial melting was not attended by obstructed masses of augite.\ This quadrangle includes the exposed at the Tatham cutting in West Spring­ Range, the striae run southwest, and thus the ice drainage, and the waters escaped eastwardly with transverse portion/of the great Holyoke The main field, and at the Holyoke Branch Railroad east of at one time moved almost directly into the mouths freedom and have left few large deposits of post­ bed from near its east end to the apex trap sheet- Ashley Pond. It is thinner than the main sheet, of the gorges. This occurs in the Pochassic Hills, glacial sands. of Mount Tom, beyond which it drops to a lower being 50 feet thick in West Springfield, and west of Westfield village, and north of the West- An exceptional deposit occurs in Granville south of the West- level and continues south. It commences with identical with it in character and composition. field River. To the north the striae have the field Little River. Flowing northward between Russell and Westfield this stream was dammed by the Con­ southerly dip and swings round to an easterly dip The bold hill east of Mount Tom and north of normal southerly direction. This seems to be necticut Valley ice lobe, extending south across of about 30°. At its east end it is thinner and the Holyoke reservoir (Little Mountain) seems to explained by the widening of the valley, which Westfield, while its upper drainage area was still more weathered than farther west, and more amyg- be the site of the vent up through which the lava caused the valley lobe of the retreating ice to fan occupied by the melting ice. The drainage off the ice in the Westfield River Valley may thus for a time have been directed daloidal. The rock is generally very fine grained, of the posterior sheet came. It is possible, how­ out here and move southwest on its western flank. southwestward up the lower reach of the Westfield Little River but at Titans Pier it is coarser, the flat blades of ever, that the hill is composed of a _, , Glacial gorges and potholes. The main trunk to the bend north of Granville. The waters then flowed ' -L Place of out= southward from this great bend, east of Cobble Mountain augite being nearly an inch long. It often shows volcanic core of later date, thrust up Hampden16 of the Westfield River seems to have been occu­ past the site of Granville village, and into the valley of the east a rude columnar structure, generally on a large through the Hampden sheet itself as sheet' pied by a body of water during and at the close branch of Salmon Brook. They spread broad areas of sand scale. Titans Piazza, south of Mount Holyoke, well as through the sandstones. The outcrops, of the Grlacial epoch, and fine potholes have been at the base of Cobble and Sweetrnan mountains and all down the central part of Granville and into Granby. The Connecti­ is much visited because of the fine col­ though abundant, do not quite settle the matter, left at Salmon Falls and below Russell. The cut Valley ice lobe, which dammed the mouth of Little River, umnar wall. The great columns are but the weight of the evidence is strongly in favor gorge of the Westfield Little River is the wildest, must also have rested against Sodom Mountain and dammed the gorge of Munn Brook, because the sands east of Gran­ here 30 to 40 feet long and 3 to 4 feet of the first supposition. most picturesque, and most inaccessible canyon ville spread to the upper entrance of the gorge of this brook, wide. They are underworn so that one, and in Starting at Smith Ferry, the Hampden sheet forms the in central Massachusetts, and here also potholes and look down unsupported upon the open valley several some places two, rows are retained in place solely crest of the ridge nearest the river for a long way south, and occur in great numbers and of the largest size. hundred feet below. Considering the great volume of sand can be seen to rest upon the sandstones as a normal contem­ and the southwestern direction of the lower part of the Little by their lateral connection with adjacent columns poraneous sheet. At Little Mountain it is suddenly pro­ Glacial deposits. The coarse upland till or River gorge, it is probable that the glacial waters, deflected by and their bottoms are hemispherical. They form longed downward as a great core, a third of a mile across, bowlder clay covers all the plateau. Over the the ice lobe which rested against Mount Tekoa, flowed up this which sends out horizontal dikes into the sandstone to the portion of the gorge from the lower valley of the Westfield thus a curious cave or rock shelter, with its ceiling west, south, and east, and overflows to form the trap sheet. valley bottom the till is also thick and continuous, River. These broad, flat-topped sand flats have a fixed shore formed of the rows of great hemispheres of the The latter extends north and east, while the parts which and is for the most part made up of the debris of line against the rocks, but they are deeply trenched by brooks column ends. The thick bed rises above the formerly extended west and south have been eroded away. the red sandstone, but the ubiquitous bowlders of that run out from them north, east, and south, and their This core, is represented on the surface by the sudden widen­ gathering is hardly explicable except on the assumption that sandstones because erosion has removed these ing of the diabase sheet. the Vermont Cambrian quartzite are found every­ all these outlets but one were closed by ice during the filling from its flanks. Its own shape depends locally where, and down to the south line of the State of the basin. * See paper on diabase, pitchstone, and mud enclosures of upon the angle at which it is truncated by erosion. the Triassic trap of New England, by the writer: Bull. Geol. bowlders of the Belchertown tonalite occur, show­ Lakes of the Connecticut Valley. As a result Where its eastern slope agrees pretty closely with Soc. Am., Vol. VIII, p. 59, 1897. ing that the due-south movement of the ice in the of the melting of the glacial ice, the Connecticut Basin in Massachusetts was occupied by three east, and south sides received no considerable retreat of the glacial ice in the Connecticut Valley cut into the soft deposits. Being in consequence confluent lakes, whose extent within this quad­ tributaries, the lake basin was much less filled were not a single event. Between the first advance loaded with sediment, it cut. into its banks, first rangle is shown in fig. 2. The northwest corner oJ than the others. marked by the lowest till, and the final retreat on one side and then on another, and Terraces of the Springfield lake, between South Theg r. The Southampton-Westfield Valley is occupied occurred several episodes of retreat and advance thus meandered in increasing curves the Connecti­ fieldlake- cut River. liadley and Springfield, extends into by a part of the south lobe of the Hadley lake, of greater or less extent and duration. These from side to side of the valley. In this quadrangle. The contrast in temperature which is separated from the northern basin by events are recorded in alternating beds of till and thus sweeping across the plain the river cut level north and south of the Holyoke Range was great, islands of Juratrias sandstone. Sands brought sands, which may vary from place to place and benches, upon which its floods spread deposits of and the ice melted south of the mountain while into the lake by the Manhan River are not often completely exposed. sand and silt. it lingered north of it. Thus the Springfield lake were spread at the highest water level Ud poTe?tyn In the long cutting of the Canal Railroad extension near the The terrace sands are medium, buff sands, deli­ was formed while the basin of the Hadley lake and joined with the great delta of the Camp Meeting grounds on the north line of Northampton, the interlocking of the till and sand deposits showed cately cross-bedded by the fine variations of the was still filled with ice. Waters flowed over the Westfield River. Thus the broad Hampden clearly that the ice after receding from this point current that spread them. A rich layer of loam in the valley twice readvanced over it. The North hamp- ice and through the notches, sweeping with them plains were formed. In the most sheltered part ton. or loess, often 8 feet thick, is spread over the sur­ section indicated that the flat-topped shore bench bodies of coarse sand, which were deposited in of the basin the sands surround the large depres­ may elsewhere also have a structure 'of unexpected com­ face of the completed meadow. It is the aggregate the northwestern part of the Springfield lake. sion of Hampton Pond. plexity. The peak of a fine drumlin was uncovered, and from contribution of many floods, its bedding destroyed The great sand bar that stretches from Titans Pier to the its south end a great morainic talus of coarse bowlders by wind, weather, and frost, and it forms the most north of Bachelor Brook, east of the Connecticut, is composed Imagine the sands restored to the old level in the area sub­ extended, the drumlin having been molded beneath the ice of sands that must have come through the Holyoke notch and sequently eroded by the Westfield River and a great plain and the moraine being made afterward of coarse, loose mate­ fertile soil in Massachusetts. The river has swung over the surface of the ice covering the region north of Mount formed by the union of the Hampden plain north of the river rial as the ice withdrew. Above these a layer of pink beach far to the west, forming the broad Hatfield and and the Poverty plain south of the same. The plain, if thus sands, at times 12 to 15 feet thick, was spread. These sands Holyoke. The reason for believing that the sands came over Northampton meadows, and to the east building the ice is because they commence in the notches at levels restored, would now slope gradually southward from 290 feet were wholly unlike the rapidly gathered angular glacial sands, above that reached by the Connecticut lakes, arid because the above sea level to about 280 feet in the latitude of The Notch, being perfectly rounded and sorted. This represented the first up the rich meadows of Sunderland and Hadley. plains north and west of the range are underlain at low level by and then rise again southward where the delta sands of the period of recession of the ice, which may have been of consid­ Westfield River extended across to abut against Proven erable duration. A fine layer of till 4 or 5 feet thick was car­ Above Holyoke the river quickly cut down to rock, and runs fine clays, showing that in the Hadley lake there was no cur­ in a narrow rock-bordered channel. South of this it has built rent able to move coarse sands southward through the notch. Mountain. The name "Poverty plain" is an expressive one ried over this sand, contorting and eroding it for a long way for these extensive and desolate reaches of coarse sand. south of the drumlin, and this marks the first readvance of up the Willimansett meadow, swinging east to Extensive sand plains stretch west from the old mouth of form the high, steep scarp that bounds the broad The wnii- the Chicopee River at Colling station and cover almost the the ice. This was covered by heavy sands of the common high ter­ sand plain to the east, built by the lake. The mladow. whole area across Chicopee, Springfield, and Longmeadow. The shore bench of the Hadley lake adjoins the Crowfoot Brook at the foot of this scarp is a The great plain now sinks from about 260 feet above sea in race type, 22 feet in thickness exposed, dipping southward 20 to low lake bottom by a steep scarp along delta 30 degrees in great sheets with strong cross bedding, and trace­ good illustration of what is called below the repulsion of trib­ South Hadley to 200 feet in Longmeadow and Agawam, and utaries. In swinging westward from the foot of the scarp the its sands grow finer in the same direction becaus'e the distance fronts, and by a long, easy slope where deltas did able south in unbroken exposure a quarter of a mile. Each great inclined sheet becomes horizontal and extends south, river built the meadow up as a series of islands, and the trib­ from the center of supply increases in this direction. The not form, as along the north foot of the Holyoke utaries found their way round the lower ends of these islands Westfield plain just west of the notch of the Westfield River gradually thinning, and being continued as a film of sand and Mount Tom ranges, or around the drumlins. between layers of fat clay, into which the sand grades. to join the river as far down stream as possible. The river in the trap range stands 70 to 80 feet higher than the Agawam then swung east to form the meadow south of Ashleyville, but plain just east, because it stands nearer its source of supply was not able to go farther east because of rock near the bridge the Westfield River which entered the lake west of West- over Chicopee River. field, and was therefore filled to a higher level; and because South of Brightwood the terrace system is broader, more there was small transfer of sediment through the narrow complicated, and more interesting. The highest terrace made notch in the trap ridge. by the river on the east side follows the 100-foot contour line These great lakes received fine sediments as from Brightwood through the thickly settled parts of the city of Springfield, running just beneath the armory grounds and well as coarse, and clays were deposited over all ending near the mouth of the Pecowsic Brook. When formed the central portions while the deltas the terrace was bounded outwardly by a smoothly curved advanced from the shores. Growing scarp, which is now cut back by many small notches caused ITT IT s»n«ls. by springs and more deeply indented by the depression in into the lake the deltas covered, the which the Boston and Albany Railroad reaches the plain and clays, and the later erosion by the river discloses by the Mill River. Each of the three principal streets running parallel to the river, Chestnut, Main, and Water streets, buff sands underlain by clay which rests on till. occupies the flat of a terrace formed by the Connecticut; and These clays are at least 160 feet thick in North­ Round Hill, north of the Memorial Church, is a remnant of the 100-foot terrace which the stream has not worn away. The ampton. They are in layers two-fifths of an most probable explanation of this hill is that the Connecticut inch thick, the lower portion of the finest clay, formerly flowed east of it, and bent westward toward River- grading into very fine sandy clay in the upper dale on the north and toward West Springfield on the south, forming an oxbow around this hill and then cutting off the part. The lower portion was deposited when oxbow in the neighborhood of the upper bridge and running the lake was frozen over, in winter ; the upper, west of the island. In order to understand the complex and beautiful system of during the floods from the melting ice, in summer. terraces around Springfield, one must suppose the old lake Beneath the till are the Juratrias sandstones. bottom restored. The 200-foot plain east of Lis- Thus the beds of thin-laminated clays, which are wells Hill in Agawam was" then continuous with the^erraces the 200-foot plain north of Mittineague, and the around worked for brick from Chicopee to Greenfield whole was continuous eastward at the same level pring ie and in the Westfield basin, have been exposed in over all the low ground of Agawam and West Springfield with the 200-foot plains north, east, and south of Springfield. It the bluffs formed by the wear of the rivers in the was an unbroken area of the same coarse sands found in the edge of the old lake deposits. remnants that are left, and underlain by the same clays that The slope of the lake beds across Springfield now crop out everywhere from beneath these sands. The Connecticut, on the disappearance of the lake, ran down over from Collin's bridge in the next quadrangle east the lowest part of the plain, not very far perhaps from its down to the plains of Agawam is slight and present course. It swung east, lowering its bed meanwhile, to its most easterly limit. It then ran at the 120-foot level from gradual, and the surface is not divided by any Riverdale south to the headwaters of Threemile Brook, and scarp or marked slope. This indicates that the then southeastward to its present bed opposite Longmeadow conditions of deposition were nearly uniform station. It swung east again, building up the plain at the 120-foot level. This, as the oldest plain of the series, has throughout the lake, and not, as in the Hadley suffered most from later erosion, but is well preserved about lake, markedly different according to the material the head waters of Threemile Brook. The Westfield River then entered the Connecticut just east of Mittineague. brought in by different streams. The stream then swung east until it formed the scarp east of The eastern shore bench of the Hadley lake lies Chestnut street from Brightwood to Pecowsic Brook, and along the flank of the Pelham Hills, »,. ,,. swinging west again it formed the plain along the west edge o % ' The Hadley of which this street runs and then deepened its channel to the just beyond the limits of the quad- lake- 65-foot level to form the depression east of Round Hill. Then, rangle. as noted above, it seems to have swung westward on the north and south of Round Hill until the bends touched to the west The shore line was at the level of the post-office steps in FIG. 2.-THE CONFLUENT GLACIAL LAKES OF THE CONNECTICUT VALLEY. of this hill and the stream transferred its bed suddenly to the Amherst. The College grounds and the Prospect street ridge A MAP OF THE HOLYOKE QUADRANGLE, SHOWING THE POSITION OF THE THREE GLACIAL LAKES WHICH OCCU­ PIED THE CONNECTICUT VALLEY DURING THE RETREAT OF THE ICE. THE TOPOGRAPHY OF THE LAND west, leaving the hill an isolated portion of a plain at the 100- formed an L-shaped island in the lake. AREAS IS THAT OF THE PRESENT SURFACE, REPRESENTED IN CONTOURS OF 200-FOOT INTERVAL, REFERRED foot level of nearly the same age as the Chestnut street plain. The eastern bench enters the quadrangle with TO THE PRESENT SEA LEVEL AS A DATUM PLANE. At the time when the river flowed east of this hill, however, the plains around North Amherst, which are the The stratified gravels, coarse near the mouth of This was covered by a layer of till, 8 feet thick, deposited by the plain of which its surface is a part stretched westward con­ ice, which wore down so as to rest on the drumlin, and then tinuously, forming part of the plain on which Riverdale stands. delta of Cushmans Brook, which entered the lake the old streams,' as at the head of the The_. Hadley ., rode out on the sands and clays, wrinkling them up into com­ The Connecticut, after forming this oxbow, moved west as far near the upper Cushman mill. The great Florence South Leverett plain, at Ctishman's lakebottom- plex patterns, pressing its bowlders down into the sands, as Agawam village, and then bore east again to its present mills in North Amherst, and at .Leeds,Leeds, grow combing filaments of the sand up into the till, and producing position, while the Westfield River lengthened eastwardly to plain, extending north into Hatfield and south by pressure a slaty cleavage in both the sands and clays, keep in touch with the main stream, and swung north and into West Farms and Loudville and east to under­ gradually finer away from the head of the delta, which was curiously brought out in the cutting when frozen south, carving its own terraces in the deposits formed by the lie all the settled portion of Northampton, is the as across the Florence plain. In passing into the by the etching of the wind and the sun. This third till was Connecticut. covered by a third series of coarse, cross^bedded sands of the The southward course of Threemile Brook, as well as the delta of the Mill River. Its great size is due to deeper and quieter waters of the lake the sand common type, which had been planed down by the waters to peculiar course of the Westfield River below Mittineague, are the fact that it received the floods from the melt­ layers grade into the delicate sand films which the horizontal surface of the lake bench. ;ases of the repulsion of tributaries as described below. part the clay layers. The last advance of the ice over the sands and clays was of A few rods north of the mouth of the Freshman River in the ing ice over the western hills, after the broad wide extent. The clays are finely contorted a few rods west bank of the Connecticut south of Hadley, where a fresh expo­ valley had become an open lake. With the rise of each spring flood a new layer of the Hatfield Hotel, in Hatfield village. The fine sands sure is maintained by the erosion of the river, show the most remarkable convolutions through 40 feet of two projections appear in the bank, marked by The old bed One must restore in imagination the sand worn away by the of sand and gravel was carried across the delta thickness and for half a mile from north to south in the rail­ T,Ibluish-gray i color-I in placei off theJ-T, buffi, « off the.IT, sands,i ofman the River. Fresh- Mill River to form alluvial meadows, and think of the Florence flat, and the finest sand was spread in a thin layer road cuttings whch extend from the south border of the Deer- There are here exposed two cross sections of the plain continuous with the plain west of the deep river bottom. far out across the lake bottom, dwindling in size field basin nearly to South Deerfield. Much farther south, a old bed of the Freshman River, deeply covered by the valley Looking west across the plain, the bowlder-covered shore hills of grain and thickness. In the winter the stag­ few rods east of the electric lighting building in Leeds, the till oam, and they contain old leaf beds with many softened and rise suddenly from the sand level ; looking east, the restored with a thickness of 20 feet rests upon the sands, which have a flattened logs of wood. The following flora and fauna have plain descends from 800 feet in Florence to 200 feet in North­ nating waters clarified themselves, and the layer great but unknown thickness. The last of these cases seems ;>een found there, which represent the climate of southern ampton, as it projected out into deeper waters. The material of fat clay resulted. It is on the surface of these to have been caused by an ice lobe coming down the Mill anada: of this delta is yellow, sorted and stratified sands and gravels, River gorge and pushing out into the open valley. The others, coarser near the mouth of the incoming stream at Leeds, finer Ranunculus aquatilis L. . Quercus alba L. exceedingly thin sand layers that fossil leaves of caused by a longer lobe coming down the Deerfield gorge, Acer saccharinum Wang. Quercus coccinea Wang. var. toward the border from Northampton to Loudville. Many Viola pahistria L., Vaccinium like oxycoccus L., extended far south, to fill the whole deep valley from old Prunus virginiana L. ambigua. bowlder-strewn islands rise above its level. Deerfield to South Deerfield and on into Northampton. Platanus pccidentalis L. Fagus ferruginea Ait. A great spur of land extends southeast from Mount Warner. V. uliginosum, Rhododendron lapponicum Wahl., Juglans cinerea L. Betula alba L. It was once a long, curved bar, which sloped gently into the Arctostaphylos al/pina Spr., A. uva-ursi Spr., Carya amara Nutt. deeper waters of the lake. The conditions along the Bay road POST-GLACIAL EPOCH. Five species of Coleoptera have been found, of which four on the north slope of Mount Holyoke are peculiar. As the ice Oxyria digyna Campd., Salix cutleri Tuck., and lave been described as new by Mr. S. H. Scudder in Mono­ melted back from the Holyoke Range, temporary lakes formed Lycopodium selago L., occur in the clays exposed Alluvial terraces. When the confluent lakes graph XXIX, Geology of Old Hampshire County. and filled with sand at a high level. The shore benph of the along the river bank below Hadley, in the clay of the Connecticut Valley had been drained, the TJie repulsion of tributaries. The very great lake was worn at a lower level into these sands, and they were partly removed and spread by undertow in a long north­ pits near the asylum in Northampton, at the Cen­ deposits of sand and clay accumulated in them suddenness of the loweringo of the lake^ _Peculiarities ,. ... ward slope into the deeper waters of the lake. tral Kailroad station, and at the clay pits near were exposed to erosion by rains, brooks, and the waters to form the present river is lakearea- Because of the greater width of the Hadley Kellogg's plane factory in Amherst. Connecticut Kiver. The Connecticut adopted a most clearly marked in the unfilled lake in its central portion, and because the north, Oscillations of the ice front. The advance and course along the lowest line of the lake bed, and Hadley lake. The deep slopes of the delta scarps Holyoke. 7 are quite intact down to the low clay flats, but a ern hemisphere tend to be deflected to the right ter, and is sold for polishing, making sandpaper, and Hartford Railroad crosses the two trap sheets, few feet above the modern terraces of the river and by the revolution of the earth. It has thrown filtering, use in the manufacture of explosives, and near the Connecticut River below Mount not notched by any terraces marking intermediate out and cut off seven great oxbows to the right, etc. The quartz is now more frequently obtained Tom station. At the last place the material water stands. The streams along the whole east­ and formed two great bends in the same direction. from large veins of pure quartz, which accom­ could be conveniently quarried and shot down to ern side of the lake from Mount Tob}7 to the In the same way the Freshman River, flowing pany and are of the same origin as the granite. the level of the railroad, and this would furnish Holyoke notch run down across the old lake .bot­ over the same plain, has formed five times as These are found of great size between the two the city of Northampton with a better material tom in accordance with its slopes, but when they many oxbows on the right side as on the left. roads running south from Chester Center and than the rock now in use. Crushing plants reach the edge of the scarp formed by the Con­ Dunes. Where the prevailing west wind about a mile east of Round Top. have recently been erected in Easthampton at the necticut River in its most easterly swing they strikes the scarp which forms the east border of Mnery. The great emery-magnetite bed in foot of Mount Tom, and on a very extensive scale bend south and take a course often for a long the meadows, the sands have been carried east in Chester has been mined for many years, first for by the New England Trap Rock Company in the distance almost parallel to the Connecticut, as if a marked line of dunes which stretch from the iron and since 1864 for emery. The TheChester north of West Springfield, where the Holyoke repelled by the latter, and at last bend suddenly Northampton road in Hadley north to Sunder- bed runs 6 miles along the east of the mine- branch of the New York, New Haven and Hart­ and enter the main stream at right angles. The land, and a similar line extends west of Hatfield. hornblende-schist, with a thickness much of the ford Railroad crosses the main trap ridge. The reason for this is found in the mode of formation way of 4 to 16 feet. The magnetite, which is works have a capacity of 700 tons a day, and can MINERAL RESOURCES. of the terrace flats of the Connecticut. As an separated from the emery, after crushing, by bat­ deliver the rock at 75 cents a ton on the cars. island is formed across the mouth of a tributary Granite. The fine granite worked by the Ches­ teries of magnets, does not seem to be utilized. Sandstone. The line of quarries extending down by the receding river, the tributary lengthens ter Granite Company at Chester comes from Becket, Much of the time the mine has been allowed to the eastern border of the quadrangle from Indian downstream and occupies the groove between the in the next quadrangle west of this. lie idle, and emery from Asia Minor and corun­ Orchard southward represents an important indus­ island and the former bank, and when with the The Porneroy Mountain granite, along bauding dum from the Southern States have been used in try. The Juratrias sandstones quarried here are continued westward swing of the main stream the east border of the plateau, is gener­ the mill instead. Recently the old mine has been extensively used for the finest buildings another island is made outside of the first the ally too coarse grained for a building stone. reopened and supplied with new machinery. under the name of Longmeadow brown- gJSfJ,0nw stream flows still farther south between this and Much fairly good rock of light color can be CJiromite. Many small openings have been stone. East Longmeadow has grown stone> the bank. In this way the tributary is sometimes obtained, and is quarried considerably in Wil- made in the search for chromic iron in the serpen­ to be a considerable town under the stimulus of deflected several miles. This is especially true liamsburg and Florence. It is all, however, too tine in Middlefield, especially a mile north of the this industry. The State was reported sixth in of the Long Plain Brook and the two brooks far from the railroad. In the western part of the point where the east boundary line of the mass the production of sandstone in 1889, with an out­ south, and of the Fort River. In the latter case quadrangle there is only one outcrop of granite. crosses the river, and in the serpentine, at the put of $649,097, of which $563,179 came from the stream once ran much farther south than This is the great Middlefield dike. The rock is " crater " in the north part of Blandford. There is Hampden County, and practically all from the Si. its present mouth, to the landing place of the blotched with white spots from the feldspar, and much disseminated ore in the latter serpentine, quarries mentioned above. The Saulsbury and Mount Holyoke steamer, and it was tapped at its so would not give an even color, and is of rather but no indication of any considerable concentra­ Kibbe quarries, near East Longmeadow, furnish present mouth by an eastward swing of the Con­ coarse grain. It would furnish large blocks and tion of the ore. the greater portion of the product, and with the necticut. The meadow flats show in broad undu­ is probably a durable rock. The dark tonalite of /Serpentine. Nearly all the serpentines in the Carlisle quarry, near Sixteen Acres, sell their lations the many islands by whose confluence they Hatfield has been quarried to a considerable quadrangle are black and hard. That at the stone at 50 to 70 cents per foot at the quarry. have been built. extent for bridge work, especially for the rail­ " crater" in the north of Blandford is pale green, The massive beds suitable for quarrying are about Contrast between the Montague and Springfield roads. It will furnish fine large blocks of durable compact, takes a fine polish, and could be used 10 feet thick and are followed above and below lakes and the Hadley lake. As detailed above, stone, which, if the lighter shades were chosen, for ornamental work. The dolomitic limestone, by thinner-bedded sandstones. The whole dips 10 the sandston'es were worn down by the ice to a might be used for darker trimmings in connection filled with black spots and bars of black serpen­ or 15 degrees a little south of east. The Jura­ low level in the Hadley lake and, protected with the Florence stone. This rock is used in tine, often in stellate arrangement, which is quar­ trias rock is generally of too coarse grain for use by the trap ridges, remain at a much higher level Northampton for macadamizing. The quarry is ried by the Westfield Marble Company mentioned as a building stone. A quarry was opened a few in the other two. As a result the latter are located where the rock is considerably decom­ above, promises to be of great value as a unique years ago in the north part of South Hadley, on "filled-up" lakes, while all the deposits were posed, and it is a rather poor road material. and attractive stone for interior decoration. a buff sandstone of good grain and color and firm insufficient to fill the deep depressions of the Flagstone. The quarries around Goshen, situ­ Lead and barite. The mine at Loudville was texture, and the town hall in Easthampton was in Hadley lake. As a second result the Connecticut, ated in the Goshen schist, formerly furnished opened before the Revolution, and was worked part constructed of it; but the rock owed its firm­

on the decline of the waters, was pushed to the many flagstones, which were used in Northampton againo in the second decade... of this cen- The Loud, A- ness to the proximity of a great mass of intrusive extreme western border of the former lakes by and the other large towns in the valley. Large tury. It was reopened during the Civil ville mine* trap, which had baked it somewhat, and the deltas, but found a low-water line down the slabs can be obtained, which consist of mica- War by a new company, and a very expensive useful stone was soon all quarried. center of the Hadley lake. As a third result, on schist, with the surface slightly roughened by plant was brought together. The company soon Clays. Brick clays are so abundant upon this commencing to lower its bed by ero- Turners small garnets and staurolites. failed, and the machinery was sold to the Chester quadrangle that they have no value when they sion, the stream quickly struck rock in Ho"yoaked Whetstone. The rock marked "Whetstone" Emery Company. The mine furnished galena with are situated away from the larger towns. All the two lakes, forming the Turners on the map is a gray, crisp, and gritty schist, with a good percentage of silver, zinc blende, and cop­ around Westfield and Greenfield basins and in Falls in the Montague lake, and the Holyoke scales of red biotite scattered evenly through the per ores, the latter in small quantity in a gangue the bluffs bordering the Connecticut River, the Falls in the Springfield lake, while in the Hadley mass and not parallel to any common plane. It of quartz and barite. It is perhaps a greater thin-bedded clays crop out in great force and are lake it flows over clays far above the rock bottom. was a sandstone in which the biotite scales have object of interest to the mineralogist, because of extensively worked, especially near Springfield This agency has located all the water powers in crystallized. Only a small part of the whetstone the rare and interesting minerals it has furnished, and Chicopee Falls. At Amherst, Westfield, the district. As a last result, the oscillations of will furnish good scythestones. The best quar­ than to the investor. The vein at Hatfield has Easthampton, and Northampton are extensive the Connecticut were quickly ended by striking ries are at the southwest base of Walnut Hill in been extensively worked by rude methods in a brick kilns. The superincumbent sands are rock in the two lakes, and therefore only narrow Huntington, and at B. Shaw's in Cummington. long line of deep pits. It is a barite-lead vein everywhere of a quality which renders them suit­ meadows were formed and the sands have been The quarries have been worked at intervals since of the same character as the Loudville vein, but able to be used with the clay for brick making. left intact, while in the Hadley lake the swing has 1830. The scythestones are sold as "Quinnebaug the barite is purer and more abundant, and it has An interesting deposit, apparently of , ._ , , . ' J. J. J White pipe been 3^- miles to the east and 4 miles to the west, stones " and are highly prized. been mined for this substance more than for the considerable importance and value, has I'SuSSS and the broad Northampton and Hatfield meadows Feldspar and mica. A series of dikes of a very metals. The two veins in Leverett, which have been opened at Blandford Center, a Center- have been formed on the west and the Hadley coarse granite forms the outer fringe around the been worked largely in the same rude way, are of white pipe clay suitable for the finer kinds of meadows on the east of the river. For this reason great granite areas which occupy the eastern edge the same kind as the others, but they are less brick and terra-cotta work. It seems to have the terraces proper that is the terraces formed of thejplateau and just enter the quadrangle on promising. been formed by the decomposition in pre-glacial by the swing of the river are more extensive in the east. This series runs up the middle of the Trap. The great ranges of trap that pass times of the feldspar of one of the beds of very Hadley lake than elsewhere, while the outward quadrangle and furnishes the rare minerals for across this quadrangle will furnish in inexhaust­ coarse and very feldspathic granite, like those bounding scarp is lower and less impressive. The which the region is noted. Around Knightsville ible quantities the best road material, Road worked for feldspar in the northern part of the steep scarps west of Northfield street or east of the region has been worked for feldspar, and and it is hoped that the recent interest material- town. It has been sheltered from the general Turners Falls in the Montague lake area, or the several dikes along this range may furnish mer­ in better roads may create here an important indus­ erosion of the ice by the hills north of Blandford. great scarp that bounds Crescent Hill in Spring­ chantable feldspar and mica. The dikes on the try. Springfield obtains stone for the city streets An extensive plant has been built at Russell to field, are sharply contrasted with the low slope north line of Blandford above the Pontoosic Flint from a quarry in the main trap ridge, on the line work the clays. The product is of the first south of Bridge street in Northampton, or that Mills have been much worked, and the quartz between West Springfield and Westfield. It is quality and has come into extensive use. The halfway between Northampton and Amherst. and feldspar crushed at the mills. The mica is only a question of transportation, and the four fine new high-school building in Northampton was Oxbows. The stream, swinging thus broadly in abundant but .not of the largest size. places where the railroads come nearest to the constructed of the buff brick from this deposit. fine and perfectly homogeneous sediments, across Qua/i*tz. The same coarse granite veins have supply of good material are at the city quarry B. K. EMERSON, the Hadley lake has been so nicely balanced that it been worked for quartz, which is extensively mentioned above, at Tatham station, where the Geologist. has obeyed Ferrel's law that bodies in the north­ crushed at the Pontoosic Mills and the mill in Ches­ Holyoke branch of the New York, New Haven May, 1897.