130 NEW YORK STATE MUSEUM 



structural and not erosional. At Binnewater such an uncon- 

 formity of deposition without erosion is seen near the old cement 

 tunnels. The following diagram illustrates it [fig. 32]. 



In the Schoharie region this change brought with it the depo- 

 sition of the Brayman shales, indicating that the source from 

 which the Schoharie region was supplied was still in large part 

 a silicious shore; the ledges of Lorraine had apparently not been 

 wholly covered by water to the north of Schoharie. Eventually 

 however the shore advanced to the limestone region, which may 

 have been where now is the Mohawk valley, 25 miles or more 



north of Schoharie. This 

 great distance of the 

 shore explains the fine- 

 ness of the material, 

 which was carried out to 

 this region, and the 

 scarcity of organic re- 

 mains which are chiefiv 

 R/i/ER restricted to pelagic ani- 



mals, some of which dur- 



Fis". 33 Irregularities in deposition of Rosendale i^g later Maulius time ac- 

 cement . 



cumulated m such abun- 

 dance as to form the greater part of the limestones. When at 

 any time the conditions became favorable, corals began to grow, 

 and their destruction helped to form the lime sandrocks found 

 at intervals in these Siluric beds. 



The shore equivalents of the waterlimes and the Manlius were 

 most probably lime sandrocks and lime rubblerocks which have 

 long since been removed by the extensive erosion to which this 

 region was subjected in Postpaleozoic time, as discussed in 

 chapter 8. The basal irregularit}^ of these deposits, i. e. the thin- 

 ning out in some places of basal members, is due to irregularities 

 of the old ocean floor, composed of the already consolidated 

 and in places strongly folded and eroded Hudson slates and 

 sandstones. 



WATBrt -S.S. 



