. Bulletin - New York State Museum. Science. i6 NEW YORK STATE MUSEUM slates on the east of the great fault. This writer makes no mention of these recent displacements in the work referred to, published in 1904. It is to be noted that the postglacial faults at Defreestville are vertical at least at the present surface of the ground, a fact which does not preclude their belonging to the class of reverse faults due to compression. Faults at Copake. The fractures in Copake are to be seen at the road corners ^ mile south of the Central New England Rail- road station. Altogether the exposures of th
. Bulletin - New York State Museum. Science. i6 NEW YORK STATE MUSEUM slates on the east of the great fault. This writer makes no mention of these recent displacements in the work referred to, published in 1904. It is to be noted that the postglacial faults at Defreestville are vertical at least at the present surface of the ground, a fact which does not preclude their belonging to the class of reverse faults due to compression. Faults at Copake. The fractures in Copake are to be seen at the road corners ^ mile south of the Central New England Rail- road station. Altogether the exposures of the phenomena at this locality constitute the most instructive assemblage of these small fractures which the writer has seen. It is stated above that this is probably the locality originally found by Mather. The slates, lying wdthin the area mapped as Cambro-Siluric. A cross-section of the postglacial faults in the vertical slates at Defreestville, N. Y. The slight westward inclination of the road is neglected in the profile. The fourth fault from the right is assumed to be .25 inches throw in the table. The oblique lines in the diagram stand for shading only. limestone on the State map of 1901, are exposed along the eastern side of the main road from Copake to Boston Corners for several yards north of the crossroads and as well on the west side of the main road in the crossroad. The following very detailed measurements were made at this locality with the view of determining precisely the rate of dis- placement for a given horizontal distance, for in this way only can the throw for the belt of fracture be determined. The first measurement was made from right to left across the area north of the crossroads shown in the photograph [pi. 4]. A tape meas- ure divided into feet, inches and quarter inches was laid over the surface of the road at right angles to the structure with the zero end of the tape on the east in each case. The surface of the rock inclined very gently to th
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectscience, bookyear1887
