﻿?6 new york State museum 



which are intercalated with these, they are also very like the Low- 

 ville, with which we at first classified them. Their shift from the 

 one to the other considerably diminishes the supposed thickness of 

 the Lowville of the district and correspondingly increases the 

 Pamelia. 



In this cut, the first of three such along the railway south of San- 

 ford Corners, the rock dip is. to the south, carrying the Pamelia 

 summit below the track level before reaching the second cut. The 

 dip then reverses, becoming north, and bringing up the Pamelia 

 again in the third cut. At the north end of this cut the basal, 

 bryozoan, conglomerate layer of the Lowville has increased in thick- 

 ness to 38 inches, as against a 3 inch thickness in the section just 

 given, and immediately beneath it is a layer of exceedingly fine 

 grained dove limestone mud, which is the exact counterpart *of the 

 material composing the conglomerate pebbles [pi. 31, lower figure]. 

 This layer was wholly lacking also in the previous section. At 

 the south end of the cut the Lowville shows 6y 2 feet thickness of 

 basal layers which did not appear in the section in the north cut, 

 and there is also a thickness of full 6 feet of the pebble-furnishing, 

 dove limestone at the Pamelia summit, which is also lacking in that 

 section. The evidence of unconformity between the two forma- 

 tions is clear, and found as Ulrich had predicted that it would be. 

 The fact that both formations thicken together is, however, some- 

 what unusual, and suggests that some of the warping shown occurred 

 in the uplift following Pamelia deposition, its summit being pro- 

 tected from wear in a shallow trough, in which also the first be- 

 ginnings of Lowville deposition took place. 



The section here in the south cut is given on page 84 under the 

 account of the Lowville formation. 



The section just described gives an excellent idea of the deposi- 

 tional conditions which prevailed during the closing stages of 

 Pamelia deposition. The fine limestone muds, much sun cracked, 

 worm-burrowed, even ripple-marked; the injection of sand grains 

 and the occurrence of the occasional limestone conglomerates, 

 together with the abundance of ostracods and the general absence 

 of marine forms; all these point unquestionably to intermittent de- 

 position in a shallow lagoon, with drying mud flats produced from 

 time to time, and with only occasional admission of sea water. 

 Though the uppermost break, here chosen as marking the base of the 

 Lowville, seems much the most considerable of all, the presence of 

 more than one conglomerate horizon, of more than one horizon of 

 sand grains, indicates several minor breaks in the summit of the 



