STRUCTURAL MATERIALS. BUILDING STONE. VARIEGATED MARBLE SOUTHEAST OF CALERA, SHELBY COUNTY, ALABAMA. By CHARLES BUTTS. About 3£ miles a little south of east of Calera, Ala., is an outcrop of marble which is attracting some attention. The deposit was noted and described by McCalley,1 and in 1910 was visited by E. A. Smith, State geologist of Alabama, to whom the writer is indebted for information concerning one of the exposures. In 1910 the deposit was also examined at one point by the writer. The exposure examined by the writer is one-fourth of a mile south of Buxahatchee Creek, in the NW. 1 NE. J. sec. 8, T. 24 N., R. 14 E., on property belonging to J. S. Evans, of Calera. (See sketch map, fig. 36, p. 222.) It is easily reached by wagon road from Calera. The exposure is on a steep bank near the head of a ravine opening into Buxahatchee Valley. A thickness of about 25 feet of marble is exposed for 50 feet along the side of the ravine. Below is an approxi­ mate section showing the stratigraphic relations of the marble. Section in ravine 3% miles southeast of Calera. Feet. Sandstone, highly ferruginous (lean ore?) ....................... 20± Shale, weathers yellowish-green................................. 20± Marble, thick-bedded, fine-grained, variegated.................. 25± Sandstone (quartzite?) coarse, with quartz veins................ 50± The sandstone at the base of the section can be followed north into the NW. \ sec. 4, T. 24 N., R. 14 E., as shown in figure 36. North 1 McCalley, Henry, Report on the valley regions of Alabama, pt. 2, Geol. Survey Alabama, 1897, pp 513,514. 237 238 CONTRIBUTIONS TO ECONOMIC GEOLOGY, 1910, PART I. of Buxahatchee it makes a high ridge, which is a good marker for the outcrop of the marble. In the bed of Buxahatchee Creek the sandstone dips 20° to 25° E., and the overlying ferruginous sandstone dips 10° to 15° E. A quarter of a mile farther east, however, the dip becomes 40° to 60° E. The geologic formation in which the marble occurs was classified as Montevallo (Lower Cambrian) by the Alabama Geological Survey. The writer concludes that these rocks are the same as those mapped by the Alabama Survey as Talladega (Ocoee) slates, which he thinks may include the metamorphosed equivalents of the Rome (" Monte­ vallo") formation. The State geologist, E. A. Smith, informs the writer that he has long entertained this view of the equivalency of the "Montevallo." in this section with the " Talladega." The marble is thick bedded, the layers being 3 to 4 feet thick. They are cut by joints that divide them into blocks of considerable size, and it seems probable that under good cover even larger blocks would exist. The dimensions of slabs or blocks that could be obtained would have to be determined by tests involving excava­ tion and the actual working of representative samples of the rock. The rock is very fine grained and takes a high polish. Part of the layers are gray and part are variegated with deep red and pale pink, the whole stratum being composed perhaps of one-half of each kind. The color is due to a coating of iron oxide on the limestone grains. The variegated layers appear to prevail in the upper portion, the gray layers below. The rock is traversed by many white and bluish- gray calcite veins, and here and there by thin stringers of small quartz grains. The variegation gives to the rock a highly orna­ mental effect when polished, and it would appear to possess superior qualities for decorative purposes. There is another exposure of this marble about 1£ miles northeast of the one just described, in the NE. J NW. J sec. 4, T. 24 N., R. 14 E., on land owned by J. W. Miller. For data concerning the marble at this point the writer is indebted to E. A. Smith, who says: "It shows a thickness of some 20 feet or more of varying shades of pink, choco­ late, and red colors, alternating with . white, sometimes in distinct bands, in some parts of rather uniform pink shade." It is assumed that the stratum is continuous between the Evans and Miller properties, but no exposures are reported between them. The topography is such that a considerable body of marble could be obtained in an open-cut quarry, but ultimately the rock would have to be mined. The outcrop on the Evans property is easily accessible to the Louisville & Nashville Railroad, about 2 miles distant, as shown on the sketch map. VARIEGATED MARBLE SOUTHEAST OF CALERA, ALA. 239 Whether the marble could be exploited with profit is a question that would need careful consideration. Competition in the marble industry is great, and it would not be easy to establish a new enter­ prise in that line on a paying basis except under especially favor­ able circumstances, as has been shown by experience in other parts of the country in the case of marble of apparently superior quality for structural or decorative use. SUPPLEMENTARY NOTES ON THE COMMERCIAL GRAN­ ITES OF MASSACHUSETTS. By T. NELSON DALE. INTRODUCTION. The granites and granite quarries of Milford, Quincy, Rockport, and Becket, Mass., were described in a former bulletin of the Survey.1 In June, 1910, the remaining active granite quarries of the State were visited and the results of these supplementary studies are here given. The treatment of the subject is both scientific and economic, as it was in that bulletin and in Bulletins 313, 404, 430, and 484, on the other New England granites. The following scale of shades and texture has been used in all these papers. Shades: Very dark gray (Quincy "extra dark"); dark gray (Barre and Quincy "dark"); medium gray (Concord); medium to light gray (Hallowell); light gray (Barre "light"); very light gray (North Jay and Dummerston "white"); white, mottled with gray (Bethel). Textures: Coarse, with feldspars over 0.4 inch in diameter; medium, with feldspars under 0.4 inch and over 0.2 inch; fine, with feldspars under 0.2 inch; very fine, with feldspars under 0.1 inch. As in the bulletins named, the number of each specimen described to which that of one or more thin sections correspond is given so that the descriptions can be verified by consulting the collections at the National Museum. All the "granites" here described, as well as the others of Massa­ chusetts described in Bulletin 354, are commercially classified and sci­ entifically determined in the table on pages 286-287, which is therefore complete for this State. The total number of quarries described is 88. Quarries producing only paving, underpinning, or crushed stone have been excluded, but the felsite quarry of Revere has been included, although it is not entered in the table. ' Dale, T. N., The chief commercial granites offMassachusetts, New Hampshire, and Rhode Island: Bull. U. S. Geol. Survey No. 354,1908, pp. 90-141. 240 U. S. GEOLOGICAL SURVEY BULLETIN 470 PLATE V MASSA CffUSE T TS H A M P S ! RHODE ISLAKD MAP OF MASSACHUSETTS, SHOWING GRANITE-QUARRYING CENTERS. NOTES ON COMMEKCIAL, GRANITES OF MASSACHUSETTS. 241 The word "granite" in the title is used in its commercial sense and embraces a variety of igneous rocks. The local or trade names of the granites used hi this paper have no significance as geologic formation names. The elementary facts as to the origin, composition, physical properties, texture, and structure of granite, together with a sum­ mary of the methods of classifying, testing, and quarrying it, will be found hi a form intended for general readers in Bulletin 354, pages 9-72. The definition of the mineral composition of granite given there (p. 11) should be revised so as to make the second or plagio- clase feldspar include either one containing soda and lime, as in most granites, or one containing soda, as in some of the granites described hi this paper. This paper concludes the writer's work on the commercial granites of New England. It contains two petrographic determinations con­ tributed by Dr. Whitman Cross, of the United States Geological Survey. LOCATION OF THE QUARRIES. The quarries to be described are hi the towns of Dartmouth, Fall River, and New Bedford, Bristol County; Lynnfield and Peabody, Essex County; Monson, Hampden County; Pelham, Hampshire County; Acton, Groton, Westford, and Townsend, Middlesex County; Wrentham, Norfolk County; Brockton and Hingham, Plymouth County; Revere, Suffolk County; and Fitchburg, Leominster, and Uxbridge, Worcester County. The distribution of all the granite- quarrying centers of the State is shown on the map (PL V). GENERAL CHARACTER OF THE GRANITES 0 The "granites" of these 42 quarries fall into 14 petrographic groups: Biotite granite gneiss (Uxbridge, Pelham); biotite granite, gneissoid (Fall River); biotite-muscovite granite, gneissoid (Dart­ mouth, New Bedford); muscovite-biotite granite gneiss (Groton, Oak Hill, Westford, Fitchburg); biotite-quartz monzonite (Town- send) ; biotite-quartz monzonite gneiss (Monson); muscovite-biotite- quartz monzonite gneiss (Snake Meadow Hill, Westford); biotite- muscovite-quartz monzonita gneiss (Acton); hornblende granite (Wrentham); horablende-augite granite (Lynnfield, Peabody); bio- tite-hornblende (or altered augite-hornblende) porphyritic granite (Brockton); mica diorite (Leominster); aplite (Hingham). GEOLOGIC OBSERVATIONS AT QUARRIES. At 12 of these quarries matters of special geologic interest were noted. These follow under various headings. 94174° Bull. 470 11 16 242 CONTRIBUTIONS TO ECONOMIC GEOLOGY, 1910, PART I. INCLUSIONS AND CONTACTS. The muscovite-biotite granite gneiss of the Rafferty quarry, in Groton (p. 264), contains several inclusions, the largest of which, triangular in outline, measures 30 feet on one side and 8 feet on another. This rock (specimen D, XXX, 100, a) is a dark-gray biotite granite gneiss with porphyritic feldspars up to 0.6 inch.