42 NEW YORK STATE MUSEUM 



Pleistocene deposits are widespread, being especially thick in the 

 more prominent valleys where the ancient rocks are in many places 

 effectually concealed. The general movement of the great ice sheet 

 was a little to the east of south across the quadrangle. 



Phelps quadrangle. This quadrangle was surveyed some years 

 ago by D. Dana Luther, but as some refined points have come up 

 for discussion and determination, certain of these were specially 

 restudied by George H. Chadwick, whose report follows. Mr 

 Chadwick's determinations are supplementary to Mr Luther's and 

 will be utilized in the publication of this survey. 



The waterlime strata (Bertie and Akron) extend across the northern 

 end of the quadrangle paralleling the railways, and have been 

 washed fairly clear of drift by the glacial drainage that followed 

 the Victor-Phelps channel. Good, continuous sections are scarce. 



The best exposure is the new quarry at Oaks Corners, near the 

 east edge of the quadrangle. This is, in fact, an unusually instructive 

 locality. Basal layers of the Onondaga limestone cap the west wall 

 of the quarry. At some points these rest directly on the Silurian 

 waterlimes, while at others within a few rods 2 or 3 feet of black- 

 pebble conglomerate varying to a nearly pure coarse white sand- 

 stone may intervene. The numerous fossil corals in these lentils 

 indicate that they may be early Onondaga (Springvale ?) rather than 

 Oriskany. 



Remarkable evidence of pre-Onondaga weathering is seen in the 

 underlying dolomitic waterlimes, while " Oriskany " sand is found 

 infiltrating fissures in these beds even 25 feet below their present 

 upper limit. The contrast with the Onondaga layers above is 

 further emphasized by the development of a peculiar system of 

 sloping joints in the weathered waterlimes, rendering them difficult 

 to blast. 



No difficulty is experienced, at this quarry in identifying the 

 minor subdivisions of the group that were instituted for the western 

 sections (Bui. Geol. Soc. Amer. 28: 173). The upper 14 feet of beds 

 of geodic cavities and small Stromatopora are the Akron dolomite. 

 Beneath are nearly 8 feet of hard, dark (" black ") waterlime refer- 

 able to the horizon of the Buffalo or Williamsville cement bed, 

 (" Buffalo " is preoccup'ed) and nearly 4 feet of bluish, argillaceous 

 limes representing the Scajaquada shale. Drillings in the quarry 

 floor have shown that the latter division continues downward for 

 another 4 or 5 feet and is then succeeded by the typical chocolate 

 dolomite of the Falkirk division. After 6 or 8 feet farther, however, 



