. Bulletin of the Geological Society of America. Geology. 250 J. F. KEMP—ROCKS OF THE EASTERN ADIRONDACKS. logical Survey. All run in a direction of about N. 60° E. and cut the strike nearly at right angles; but as this varies from N. 10° E. to N. 40° W., or even more, the statement is not always strictly true. Figure 3 represents a cross-section through the large ophicalcite quarry of Mr Treadway, half a mile north of the town, and through a lower lying white limestone, well opened for furnace stock. It shows below this, after a concealed strip, mica-schist, black garnetiferous hornblende- sc
. Bulletin of the Geological Society of America. Geology. 250 J. F. KEMP—ROCKS OF THE EASTERN ADIRONDACKS. logical Survey. All run in a direction of about N. 60° E. and cut the strike nearly at right angles; but as this varies from N. 10° E. to N. 40° W., or even more, the statement is not always strictly true. Figure 3 represents a cross-section through the large ophicalcite quarry of Mr Treadway, half a mile north of the town, and through a lower lying white limestone, well opened for furnace stock. It shows below this, after a concealed strip, mica-schist, black garnetiferous hornblende- schist, more white limestone and black schist, and finally the great in- trusion of gabbro at the OPHICA LCIT E NhbUE Figure 3.— Cross-section at Ophilcalcite Quarry, near Port Henry, New York. The arrows indicate the strike in plan. The general dip is a flat one of about 20 degrees, as a maximum, to the west. Over the ophicalcite is light gray gneiss, with additional ophicalcite showing higher, but farther south. Still, dips are quite un- certain quantities in these dynamically metamorphosed beds, and are mostly, for individual beds, pressure-effects as shown by sheared inclu- sions. Where there is a change from one kind of rock to another a con- tact-dip, however, is developed which is worthy of the geologist's serious consideration. The topography indicates that there is a great fault to. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Geological Society of America. [New York : The Society]
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectgeology, bookyear1890
