sign in sign up
<<
Home , Durand Eastman Park, Glacial erratic, Kame delta, Kettle (landform)

anthropogenic (created by humans) landscape, into horse-drawn carts and carried away, In EVERYTHING YOU Indeed, it was the steep-sidedness and irregu- contrast, the continuous use of Mount Hope as WANTED TO KNOW larity of the area that probably led to its use as a cemetery since 1838 has also preserved an a burial ground; it was picturesque, and, after incomparable glacial landscape, ABOUT THE GEOLOGY some initial gravel quarrying, it apparently OF MOUNT wasn't good for anything else, The former St, Mount Hope Cemetery was built on the eastem HOPE CEMETERY Patrick's Cemetery on Pinnacle Hill was quarter of a row of hills called the Pinnacle apparently built on its site for similar reasons, Range, In a city where topographic drama is by William Chaisson However, consolidation of the neighborhood elsewhere provided by holes in the ground like Catholic cemeteries to Holy Sepulchre in the the Genesee Gorge, the Irondequoit \'alley, and

(Editor's Note. Bill Chaisson is a professor of Here, looking north from Lawn Avenue in the gullies of Durand-Eastman Park, the geology at the . In this Section E, is a conical hill formed by a Pinnacle Range represents the only significant positive relief, The Pinnacle, the tallest hill in article, he takes us through mythological ideas and known in geological terms its a , It is about the formation of the earth's surface to the range, lies between South Clinton and formed when a glacier deposits into a the major scientific discoveries that ascertained Monroe avenues and rises 263 feet above the in front of the . the existence of massive global that surrounding plain, The knolls of the by created the interesting landscape of Mount Photo Frank A, Gillespie. Irondequoit and Durand-Eastman Park Hope Cemetery and the surrounding area, are incidentally left standing higher as a result These glaciers present a fascinating story, and of running water incising and eroding the sedi- a tale that is true,) ments around them, while the Pinnacle Range late 19th century permitted the resumption of hills were actively built during the latter states The jumble of hills and glens in Mount Hope quarrying at Pinnacle Hill, As a result, much of of the last glacial retreat, Cemetery is a largely natural rather than an the natural shape of Pinnacle Hill has been put HISTORICAL found over much of Europe and North America, In 1840, he published "Etude sur les BACKGROUND Glaciers," wherein he proposed the existence of a global in the geologic past, The Pinnacle Range entered the geological lit- Agassiz was an enthusiastic and tireless lectur- erature in 1843 when James Hall, er, and he immediately began a campaign State geologist, published the first description throughout Europe to replace the diluvial theo- of the ridge, He included a sketch of the sedi- ry with the glacial explanation for drift ments revealed by the excavations done to deposits . lower the grade of Monroe Avenue on its way out of the city and into Brighton, At this early In 1846, three years after Hall's initial exami- date, Hall would not have guessed the true nation of the Pinnacle Range, Agassiz moved agent for the construction of hills, From the Sedimentfrom the ice sheet is to the United States and published "Systema 17th half of 19th the to the latter the century, deposited in layers into Glaciare" ( 1847) on the strength of extensive scientific community generally accepted the Danaforming the . field work throughout Europe, After 1848, he hypothesis that Noah's was responsible accepted a professorship at Harvard University, for the form and distribution of much of the did more field work in North America, and unconsolidated material found on the Earth's actively introduced the glacial theory to the surface, Because this debris was thought to New World geologic community, Largely have been transported and deposited by water, because of more rigid religious beliefs from it was called "drift." those of their European colleagues, the North American geologists took longer to be won During the Renaissance (15th and 16th cen- over, As late as 1891, prominent Canadian turies), scientific explanations for natural phe- geologist Sir J, William Dawson (1820-1899) nomena began to replace mythological stories, was still actively defending the diluvial theory, The hypotheses to explain the form and opera- The ice sheet retreats a short distance which had long since been abandoned by the tion of Nature became increasingly ambitious from the kame delta and continues to European establishment, in the 17th century . Thomas Burnet (1635- deposit infront ofit. 1715), royal chaplain to King William III of But through the second half of the 19th centu- , published his "Telluris Theoria ry, the glacial theory gradually gained more Sacra," or "The Sacred Theory of the Earth" in American adherents . In 1890, geologist 1861, One of Burnet's primary assumptions Charles Dryer noted that the lower half of the was that he was living in a "fallen world." Pinnacle Range was composed of coarse grav- Before the commission of the "original sin," els, while the upper half consisted of fine the world had been a perfectly orderly place, sands, He called the entire ridge a gigantic Burnet sought to explain the , decay, "kame," a term of Scottish origin that refers to and disorder that he saw on the landscape, and layered or stratified that are derived he attributed much to the violence and scale of from a glacier, but deposited into a body of the Noahic flood, Through the 18th century, as The ice sheet re-advances onto water, Two years later, another geologist more field work led to more extensive map- the kame-delta, deposited Warren Upham, impressed by the linear form ping of drift deposits, this "diluvial theory" unlayered and unsorted of the chain of hills, claimed it was a very was gradually refined, It would have been material over the kame sediments. large ";" the sediment accumulation in the Hall's assumption, as he sat in the middle of a channel of a sub-lacial river. In 1895, Herman construction site on Monroe Avenue in 1843, LeRoy Fairchild (1850-1943), a geology pro- that he was sketching sediments deposited in a fessor at the University of Rochester, showed global flood, that Dryer was closer to the truth than Upham.

In the 1930s, Swiss paleontologist and zoolo- gist (1807-1873) began taking walks in the with mountain guides . These were men with little education, but years of experience traveling in the mountains, They showed Agassiz the deposits left on valley ice sheet retreats to latitude floors after glaciers had melted back decades The the of before, The professor was struck by how simi- thepresent shore ofLake . lar these alpine deposits were to piles of drift Glacial Lake Dawsonforms at a lower that he had observed much further north in level than Dana and the southern , some distance from the kame-moraine is left exposed mountains, Using the premise that similar to erosion. results have similar causes, Agassiz hypothe- sized that the alpine glaciers had been much more extensive in the distant past, Agassiz threw himself into the scientific literature on this new topic and found that drift deposits similar to the alpine glacial sediments could be

for hundreds of miles . At the edges of the ice Lake Dana." Most of the glacial were sheet, this load of sediment was disgorged. named for famous geologists. Consequently, GEOLOGY Sediment ejected from a glacier is collectively the lower half of the Pinnacle Range consists referred to as "till," which is essentially syn- of stratified sands and gravels, as described by H. L. Fairchild's major achievement as a onymous with the historical term "drift." Dryer, and is, as he claimed, a kame deposit. It research geologist was his mapping of a series is part of a longer feature that extends west- of glacial lakes that ponded in front of the Ice sheets and glaciers "retreat" when the rate ward, which is sometimes called the retreating continental ice sheet at the close of of melting at their perimeters exceeds the rate "RocHester-A INon moraine." the last glacial cycle, which was between of ice accumulation at their centers. When 18,000 and 9,(X)0 years before the present time these rates are exactly balanced, the edge of Fairchild described the Pinnacle Range as a (B.P.). The topography of the ice sheet will remain in the same place and "hybrid structure" called a "kame-moraine," State rises steadily from the Lake Ontario continue to eject till, building up a long linear because the hills, although stratified at the basin to the , which is why pile along the perimeter. Such a pile at the base, have an unstratified "crown" that is in the Genesee River flows north, As the southern maximum extent of an ice sheet is called a many places full of large boulders. Fairchild edge of the ice sheet retreated northward "." Accumulations that are reasoned that the ice sheet must have retreated across the state, the collected deposited during standstills in the course of thee northward a short distance from the "kame between the towering ice mass to the north and ice sheet's retreat are called "recessional delta" it had built into Glacial Lake Dana. A higher ground to the south in a series of enor- moraine",. brief re-advance of the icefront then reached mous "proglacial" lakes. Fairchild gave each the crest of the ridge and remained there for a lake a name as it dropped to a lower level and If till is ejected from the ice sheet directly onto relatively brief period of time, leaving a thin drained either west through the Mississippi the landscape, it collects in an unlayered "icing" of moraine atop the layered "cake" of drainage or east through the Mohawk or St. deposit and is composed of every conceivable the kame, Lawrence Valley. grain size, all mixed together. All moraine (there are many forms) has this unstratified, The final retreat from the Pinnacle kame- By approximately 10,000 years B.P., the south- unsorted character, However, if till is washed moraine was associated with a drop in the lake ern edge of the ice sheet had melted back to out of an ice sheet in a meltwater stream and i.s level, and the water body in front of the ice the latitude of Rochester. The center of this brought into a glacial lake, the resulting sheet became "Glacial Lake Dawson." The ice great ice mass was over the northern part of deposit is both layered and sorted (i .e., the var- front was then located roughly along the pres- Hudson Bay, . For tens of thousands of ious types of kame). Smaller sediment grains ent shoreline of Lake Ontario. The shoreline of years, it had been so cold there that the snow remain suspended in the water column longer Glacial Lake Dawson was below, the ridge on that fell each winter was not entirely melted and are carried further from the ice sheet which Mi. Hope Avenue and East and West away during the succeeding summer, causing a source, As a result, clays accumulate several Henrietta roads are built, This height of land net accumulation of snow. Over millennia, this miles from the ice front and large boulders separates the modern Genesee watershed from accumulation became so thick that the perenni- may be found immediately next to it, with a the Irondequoit Creek drainage, Lake Dawson al mow' %% as condensed to ice. Eventually the more or less continuous gradation in size filled the Irondequoit Creek watershed, but a ice was condensed to the point where it between these two extremes . smaller glacial water body called Glacial Lake became a plastic solid, flowing away from the Scottsville remained in the Genesee Valley thicker center toward the thinner edges. between Rochester and Avon. The dam that PINNACLE RANGE created the lake was the Albion-Rochester Over approximately 100,000 years (120,000 to GEOLOGY (kame-)moraine, which crossed the valley at 20,000 B.P. [before present]), the latest incarna- the present site of the River Campus of the tion of this continental ice sheet grew from its When the "Ontario lobe" of the "Laurentian" University of Rochester. center near northern Hudson Bay to cover a ice sheet reached a standstill over Rochester third of North America. This most recent gla- 10,000 years ago, it was depositing debris into The ice sheet was apparently melting very rap- cial advance is called the Wisconsinan, a that Fairchild called "Glacial idly as it built up what became the Pinnacle because significant glacial deposits can be found in that state. Traditionally, three previ- ous glacial advances are described from the North American continental record (the Nebraskan, the , and the Kansan) with corresponding coeval deposits found in Europe. However, over the past 25 years, analyses of stable isotopes in deep-sea carbon- ate records have revealed that the latest ice age in Earth history began approximately 3.2 mil- lion years ago and that the amplitude of gla- cial- cycles has been gradually increasing since then.

its enor- The plastic consistency of the ice, The figure on the left shows the distribution of ice blocks and sediments during mous weight. and its dynamic nature caused it glaciation . Thefigure on the right shows the corresponding distribution ofkettles and to tear apart the landscape as it moved over it. of ice sheet. Illustrationfrom Monroe & Wicander Pieces of of all sizes-from clay particles after the retreat the to blocks as big as buildings-were absorbed 2001), THE CHANGING EARTH: EXPLORING GEOLOGY AND EVOLUTION, into the ice mass and carried along, sometimes Brooks/Cole, Pacific Grove, CA. Grove Avenue: divides Mount Hope Cemetery Range; whole sections of the icefront were col- into two distinct physical relief areas. South of lapsing . The evidence for this is the abundance GEOLOGY OF MT. HOPE of kames and kettles along the length of the Grove Avenue (to the left), the ground is flat or CEMETERY range. While "kame-deltas" and "kame ter- slopes in smooth planes, North ofGrove Avenue, the land slopes upwards to an races" are linear features (the latter collect Till and Moraine between a retreating ice sheet and a valley wall undulating landscape that is filled with kames, and can be found in the region) . kettles, and . Ice sheets have a parabolic profile ; they thin kames, essentially, are actually conical hills. Photo by Frank A. Gillespie. very gradually toward their perimeters and The term "kame" refers to the mode of forma- then have very steep edges. The Laurentide Ice tion and their stratified appearance rather than Sheet is estimated to have been 14 kin (9 the gross form of the feature, miles) thick at the center. Imagine the roughly till, becoming partially or completely buried, circular ice sheet with three concentric zones When a boulder or a till-rich portion of ice is Insulated by the surrounding sediment and its around its center . The center area was the zone exposed on top of the ice sheet as it is dis- own bulk, such an ice mass may take decades of accumulation. In the second zone, the base gorged, it will absorb heat from the sun and re- or even centuries to melt . As the ice volume of the ice sheet was primarily eroding the radiate it into the surrounding ice, melting it, slowly disappears, any overlying sediment set- Earth's surface, picking up sediment and and creating a or lake on the surface of tles downward creating a called a absorbing it into the plastic, moving mass, But the glacier. This is a positive feedback process, in the " . " outer third of its radius, the ice sheet because as more ice melts, more till is began to deposit its till load . In most places, it washed into the pond and more heatuncovered, is Because both land forms are associated with simply plastered it across the landscape absorbed and re-radiated . Therefore, this episodes of rapid melting, they are often found (ground moraine), but where the base of the water-filled depression accumulates stratified together in what are known as "kettle and ice sheet moved quickly, it sculpted the ground sediments, just as a lake on land would do. kame terrains." The Mendon area is one moraine into long distinctly cigar-shaped hills Eventually, all of the surrounding glacial ice local example and consists of very large kettles called " ." If the shape of the hill is melts away leaving the accumulated sediment and kames. The northern portion of Mt . Hope more obscure, then it may be referred to as a as a stratified pile sitting on the landscape . Cemetery is another, "drumlinoid ."

The rapid collapse of an ice front has been Mt . [lope Cemetery is divided by Grove observed at the termini of modern glaciers . Avenue into two distinct physiographic dis- Blocks of ice the size of houses or larger fall tricts . South of Grove Avenue, the ground is off the ice front and disappear into the soupy flat or slopes in smooth planes toward the west. Mt. Hope Avenue comes down off the Cobbs and Pinnacle hills. However, the most vated to flatten the area to the north for graves kame-moraine from Highland Avenue and easily observed gravel pit is "The Gully" in added in the 1890s. stays on the high ground that forms that divide Highland Park, This depression extends from between the watersheds of the Genesee River the intersection of Doctors Road and Reservoir As you follow Glen Avenue northward from and Irondequoit Creek. This low ridge is one Avenue to behind Lamberton Conservatory, Pine Avenue to Buell Avenue (between of several south of Rochester that are oriented Sections M and W), you pass out of this slightly east (4 north and arc composed of Most natural depressions are created by the depression into the kame area, A small kame what Fairchild Called "drumlinoid till." erosive action of running water. In order to lies between West Avenue and Glen Avenue carry the sediment away and create the hole, (Section R). An even smaller kame lies Because drumlins are deposited as the ice water must run downhill . The gravel pits and between West Avenue and Patriot Hill (Section sheet advances, they will be underneath any kettles are two types of depressions not created B). Both of these have the characteristic steep, kame or glacial lake deposits that are deposited by running water, so both are typically missing conical shape of karnes. A larger, more irregu- as the ice retreats, This is the case over much a low spot at their periphery that marks the lar kame is traversed by Linden Avenue of Rochester, Brighton, and Henrietta, where exit of the water that ordinarily excavates the (Section A), The northern boundary of the sediments deposited in Glacial Lakes Warren, hole in the first place. kame area is Maple Avenue. Dana, Dawson, and Iroquois blanket earlier glacial features, softening their outlines and The most easily discerned kame in Mt. Hope creating a smoothly rolling or nearly flat land- Kame Sediments Cemetery can be seen immediately behind the scape. The Pinnacle kame-moraine is one of The most difficult area to interpret in the north gatehouse (Section E) at the north the most prominent interruptions in this muted entrance off Mt. Hope Avenue, The steep coni- topography. cemetery lies north of Grove Avenue. west of Indian Trail Avenue and south of Patriot Hill cal shape has been little altered by roadbeds or (Section R), The topography is uneven and walking trails, and no other kame material is Gravel Pits and Natural includes many breaks in slope that are modifi- draped over it, A more complicated and more cations made to produce more level areas for disrupted group of kames is traversed by Depressions graves and for the passage of roads. However, Hillside, Ravine, Hope, and Indian Trail avenues (Sections G, K, F, and 1), Immediately north of Grove Avenue in the the entire area may have been an early 19th cemetery, there is a steep rise in the north century gravel pit. If the slope once led more slope of the kame-moraine that may be a evenly down to the riverside, it has been modi- Kettles wave-cut surface formed at the shore of fied in the recent past by the construction of Glacial Lake Scottsville. All of the cemetery dormitories and tennis courts immediately Sylvan Waters, surrounded by Hope, Cedar, between this rise and its northern boundary is a north and west of the cemetery fence, which and Dell avenues, is perhaps the most visible classic and dramatic kame and kettle terrain . has left a steep excavated face just beyond the and unambiguous kettle in the cemetery. Its The karnes are so numerous that some are par- fence, Let us traverse this area from Grove slopes have been modified; a terrace has been tially overlapping, perhaps representing supra- Avenue along Glen Avenue. cut midway between the grade of the Surround- glacial ponds that initially were separate and ing roads and the water's edge. The rough- then melted the intervening ice away before One of the few places in the cemetery where hewn cairn of mortared dolomite stones in the being set down into a composite pile on the the underlying glacial sediments are exposed is middle of the pond was once a working foun- land, in the cut made by Glen Avenue as it drops tain. But in spite of these anthropogenic modi- down from Grove Avenue, The sediments visi- fications, the original inverted conical shape of Because Mount Hope was set aside as a burial ble there are very, fine. well sorted sands. This a typical kettle is apparent. There is a shallow- ground in 1838, it was less subject to commer- is evidence that they were deposited into er dry kettle just west of Sylvan Waters toward cial quarrying than the rest of the Pinnacle standing water several hundred yards from the the junction of Cedar and Dell avenues. It, too. Range. In 1923, H. L, Fairchild published a ice front. Were it possible to follow these lay- has been terraced, but here it has been done to summary of his research oil the "Rochester ers at Glen Avenue laterally, one would provide a flat area for graves. Another apparent kame-moraine" in the "Proceedings of the observe coarsening of the sediment grains dry kettle can be seen south of the intersection Rochester Academy of Science." At age 73, northward and fining toward silts and clays to between Indian Trail and Dell avenues. Fairchild used this paper to wax elegiac about the south. Soil has crept down the cut made by the vanished landscape along the Pinnacle the road, obscuring the geology that was prob- Whether this last is actually a kettle depends Range. When he began observing and photo- ably revealed by the excavation . At present, upon the uncertain nature of the ridge tra- graphing the area in the early 1890s, most of the sands can best be seen among the exposed versed by Indian Trail Avenue. Steven Thomas, the range, except for the Pinnacle itself, was tree roots along the embankment. No sediment former director of the Rochester Museum and dotted with kettle ponds. In the first 20 years layering is visible here because of decades of Science Center, hypothesized that the ridge is of the 20th century, when the Ellwanger & creep and soil formation. In order to see the an esker, Geologist Warren Upham mistook the Barry horticultural nursery turned into a real strata, one would have to dig a trench into the entire Pinnacle Range for an esker in the estate company and began building houses on hillside, which would be rather frowned upon, 1890s, Eskers, like kames, formed during the the north slopes of the hills, the kettle ponds to say the least, retreat of the ice sheet. But unlike karnes, were filled in. which formed on top of or at the perimeter The presence of a retaining wall along Cedar (kame deltas or kame terraces) of the ice sheet, Depressions carved into the hillsides of the Avenue to the east of the intersection with eskers formed in tunnels through the ice that Pinnacle Range outside of Mt. Hope are often Glen Avenue (Section MM) indicates that sedi- were cut by meltwater. The meltwater was gravel pits. The Fairchild Collection at the ment has been removed from the natural slope heavily laden with the sediment that had been University of Rochester's Rare Books Division in order to construct Cedar Avenue, Westward absorbed by the plastic glacial ice as it crept includes a large number of photographs that along Cedar, there is a break in slope to the down from the north. The tunnels, therefore, show laborers, horses. and carts standing in north (toward the dormitories) that is covered filled with sediment faster than the meltwater front of enormous excavations, particularly at in sumac trees . This has apparently been exca- could expand their diameter. Once the tunnel

Four kettles tint the Mount Hope Cemetery was filled with sediment it was abandoned landscape. Here is the only one of those kettles If you pick one up, you can see that there are and remained as a sinuous, coarsely stratified to hold water, so it is called Sylvan Waters, three relatively flat facets to each one. Two deposit within the ice sheet, When the sur- The pile of in the center f facets are generally narrower than the third, All rounding ice melted away, river-shaped ridges come to a point at one end of the long axis of he snow-coveredkettle is a man-made rocksfountain. Photo byot the stone : these cobbles are generally oblong . were left snaking across the landscape. Frank A. Gillespie. The opposite end of the long axis is generally Thomas' hypothesis is tenable for at least four a rounded surface. The overall appearance is reasons. First, it is oriented roughly perpendi- ridge is knocked over in a storm, wrenching that of a stubby boat with a distinct keel, point- cular to the ice front, which is generally true of the roots from the steep, unstable hillside, then ed prow, and rounded stern . The broader facet eskers . Second, the Mt . Hope kames are a hole of sufficient size may be created for is the top of the boat with the two narrower draped over the ridge, which indicates that geological study, Construction projects to sides forming the keel . This distinctive shape they were deposited later. Kames develop on regrade roads or replace drainage pipes also is found in pebbles and in boulders as large as top of the ice sheet and so would be deposited might provide a look inside . If the Indian Trail houses, over subglacial features, Third, historical Avenue ridge is indeed an esker, it would be records document the existence of a constructed of coarsely stratified layers of The Henry A. Ward monument at the junction cast of the ridge (Section L), The ridge upon poorly sorted sediments, of Indian Trail and Cedar avenues in Section G which Indian Trail Avenue sits evidently is itself a collected in Georgian blocked the path of water draining from Glacial Erratics Bay, Canada by Ward himself. The conglomer- uplands to the south and east and toward the ate boulder is studded with red jasper cobbles Genesee River to the west . The wetland was The sediment exposed among the roots of and has the distinctive boat shape of an erratic. drained by tunneling under the ridge. Finally, wind-thrown trees on the northern slope below Conglomerates are sedimentary rocks that the name "Indian Trail" is drawn from local Indian Trail Avenue is full of glacial cobbles. include a mixture of sediment grain sires: legend that would suggest that the ridge was These stones have a distinct shape regardless some of the grains are up to several centime- not constructed, but was pre-existing from, as of their (rock type) that is a result of ters across, they say, time immemorial . being dragged across the land in the maw of a moving mass of ice several kilometers (more If erratics come from a moraine, and by defini- The only sure way to discover the origin of the than a mile) thick. Because they are wrested tion they have not been in running water, then ridge is to excavate it, which is unlikely to be from their point of origin and deposited some- the facets tend to be distinct, coming to rela- undertaken just to satisfy curiosity. In such times hundreds of miles away, sometimes tively sharp edges, If they have been picked up cases, investigators must wait for chance to perched in rather unlikely places, these stones and moved in glacial meltwater streams, they intervene, If one of the larger oaks along the are referred to as erratic,, tend to become more rounded and begin to

approach the smooth ovate shape of river hard enough to survive long-distance transport seen in the boulders. In an unaltered state, the stones . The cobbles in windthrows (areas beneath an ice sheet. In addition, marble is corals are composed of adjacent hexagonal where trees are uprooted by wind, exposing chemically susceptible to dissolution in mildly tubes, giving them the appearance of globular the cobbles) below Indian Trail Avenue are acid conditions, as is evident by the poor con- honeycombs. But the infusion of magnesium slightly smoothed, suggesting that they were THE FRIENDS dition of marble monuments exposed to urban disrupted the crystal structure of the limestone, transported in moving waterOFforMTsome. distance air pollution like acid rain, Glacial meltwater. leaving the coral heads looking like cancerous beforeHOPEbeing deposited,CEMETERYThis lendsMAKEfurther cre- laden as it is with silicate minerals, can have a cabbages . denceANOTHERto the hypothesisIMPORTANTthat the narrow ridge rather low acid pH, DISCOVERY The Silurian reefs eroded into adjacent lagoons Local Bedrock (imagine something like the modern Bahamas Rochesterians have long lamented the archipelago), filling them with layered carbon- absence of a home owned and occupied by Most of the rocks that can be found in Mt. ate mud. These lagoonal limestones were often Frederick Douglass . The discovery of the Hope Cemetery, either lying on the ground or used as building stone in the Rochester area grave sites of Rosetta Douglass Sprague, used to build the retaining walls and other before the made importation of daughter of Frederick Douglass, and her structures in the cemetery, are of local origin . exotic stone economically practical. The family in Mt . Hope Cemetery has led to All of the bedrock of western New York is of retaining wall for the cemetery along Mt. Hope another historically important discovery by sedimentary origin, which is to say that it was Avenue is composed largely of Lockport (gray) the Friends of Mt . Hope Cemetery . A deposited as layers of sediment in shallow and Medina (red) stone. The pillars that mark home owned and deeded to his daughter tropical seas that covered this area repeatedly the corners of Highland Park were originally still stands on Hamilton Street in between roughly 550 and 320 million years composed of gray Lockport dolomite, but Rochester. He is listed as a boarder at that ago. The sediment was hardened into rock by reconstructed pillars have been faced with a address in city directories for several years fine-grained gray granite, after he moved to . being buried deep within the Earth. Over the This photograph illustrates the "boat shape" past 30 million years or so, it has been uplifted ofglacialsurfacescobbles. The scratches on the When Rosetta D. Sprague left Rochester more in the north than in the south and the lay- SUMMARY to join her parentsare incausedWashington,by one cobbleDC,flattened she ers are therefore tilted from three to five deededscrapingtheagainsthouseanotherback to heror againstfather andthe he degrees to the south . These slabs of bedrock Before the last ice age, the landscape of Mount underlyingowned itbedrockuntil hisasdeaththe icein 1595sheet. transports underlie the entire western portion of the state Hope Cemetery simply did not exist, The land it across the landscape, Photo by Herman L, from the Catskill Mountains out into the likely sloped smoothly upward from the low- Midwest and the southern part of Ontario, Fairchild. "Geologic Story ofthe Genesee lands near the present location of the New Canada. Because they are tilted ("dipping" is York State Thruway to the ridge of the Niagara Valley and Western New York" (1928), the geological term) to the south and eroded escarpment, upon which the city of Rochester down, they are exposed in broad east-west is built. But between 10.000 and 9,000 B.P, bands through the Southern Tier of New York the latest ice sheet paused in its final north- upon which Indian Trail Avenue sits is an State, the Finger Lakes, and the Ontario Lake ward retreat and deposited sediment into a lake esker, There are two well known eskers in Plain. Tile oldest (deepest) rocks are exposed of meltwater ponded between its southern edge Mendon Ponds County Park, The western one along the shores of Lake Ontario and the and the land rising south of Avon, This was to is actually truncated by the New York State youngest at the Pennsylvania border. become the bulk of the Pinnacle kame- Thruway immediately east of the Clover Street moraine, a stratified bulwark of overpass. sand and silt The most abundant stones in Mt. Hope that stretched for several miles between Cemetery and other area cemeteries (aside Brighton and Albion . At the location of Mt. Many of the cobbles that are found in wind- from the monuments) are derived from the Hope Cemetery, in particular, the front of the throws have exotic . The rocks with Lockport and Medina Groups, which formed ice sheet seems to have collapsed in a rapid the most distant provenance are probably the during the Silurian Period (435 to 410 million and dramatic manner. This collapse left that gneisses, which are derived from the Canadian years ago), A "group" is a package of sedimen- part of the range a confused mass of overlap- Shield in Ontario. Gneisses have the same tary rocks that are genetically related, which is ping kame hills and kettle depressions that mineralogy as granites (quartz, feldspar, and to say that they represent a series of deposi- early settlers would one day find economically mica), but granites are igneous rocks and cool tional environments that existed subsequent to useless and later citizens would find extremely from a molten state. Gneisses are metamorphic one another in the geological past over a par- picturesque. rocks, that is, they are derived by subjecting ticular area. Groups are composed of "forma- sedimentary and igneous rocks to enormous tions," each formation consisting of sediment The geologic history of the cemetery location amounts of heat and pressure, often at great that accumulated in a distinct environment in divides it neatly into two very different sec- depths below the Earth's surface. This mode of the past. The Medina Group includes a sand- tions. The northern, more picturesque section creation causes the axes of minerals in gneiss- stone called the Grimsby Formation, which is composed of the kame-moraine itself, with es to be oriented in a consistent direction. This represents an ancient beach environment, The its chaos of kames and kettles. The southern, is particularly apparent in the dark micas. In Lockport Group includes a series of formations more orderly section is laid out on the smooth contrast, the minerals in granites are generally called "dolostones." These were originally expanse of a former glacial lake bottom, The randomly oriented . deposited as reefs and shells composed of cal- northwestern section has been altered from its cium carbonate (limestone), but during their natural state by excavations, perhaps related to The other exotic metamorphic rock that is hard burial and transformation into rock, they were the building of a railroad embankment, enough to survive being dragged beneath an infused with magnesium-rich pore waters, for more distant purposes, but in general,perhaps ice sheet from Ontario, Canada to New York which altered their molecular structure. Many we find the land much as the ice sheet left it, State is quartzite. As its name suggests, of the boulders that emerge from excavations only covered by soil,. grass, trees, and the quartzite is composed almost entirely of the in the Rochester area are pieces of the Penfield to the dead monuments mineral, quartz, which causes them to be a Dolomite formation. This represents an ancient milky white or slightly pink color. Marble, the reef, and the rounded coral heads can often be other common white metamorphic rock, is not ADDDITIONAL READING

Fairchild, H . L., 1895 . The kame- moraine at Rochester, NY. American Geologist, v. 16, pp . 39-5 I .

Fairchild, H . L., 1923 . The Pinnacle Hills, or the Rochester kame-moraine . Proceedings of the Rochester Academy of Science, v. 6, pp . 141-194.

Fairchild. H. L., 1928 . Geologic Story of the Genesee Valley and Western New York . Published by the author. The Paleozoic bedrockformations ofwestern New York. The oldest (lowest) rocks are Distributed by Scrantom's, Inc. furthest north and progressively younger r (higher) rocks are found toward the south, 'Ordovician', 'Silurian' and 'Devonian'are periods within the Paleozoic Era, Other names are those of formations.