﻿SO NEW YORK STATE MUSEUM 



Lowville limestone. The Lowville limestone which is the 

 " Birdseye limestone " of the old Geological Survey reports has 

 its maximum development in New York in the region of the 

 lower Black river, or in the southern portion of the area here 

 mapped. It reaches there about 60 feet in thickness. It consists 

 typically of thick and thin bedded, fine grained dove limestone 

 which shows a characteristic ashen gray weathering and con- 

 tains either numerous more or less vertical worm tubes denoted 

 as Phytopsis and filled with calcite (producing the " birdseyes " 

 in sections) or shows in profusion the horizontally spreading 

 tabulate coral Tetradium cellulosum and related 

 species. Between these typical Lowville beds there are inter- 

 calated others of subcrystalline dark to black limestone, or of 

 oolitic or also of shaly whitish weathering limestone. These inter- 

 calations usually contain a larger fauna than the dove limestone 

 and carry lamellibranchs, gastropods and cephalopods, as well 

 as ostracods and trilobites. 



The basal bed is conglomeratic and of very variable thickness ; 

 it is overlain by several feet of strata that contain quartz grains 

 or grit bands and are more or less shaly, the shaly limestone 

 gradually becoming more massive upward and assuming the 

 characters of the typical rock. These more or less sandy beds 

 comprise about 4 feet. 



The uppermost portion of the Lowville beds which has been 

 mentioned by the earlier authors as the " cherty beds " has been 

 found by Professor Cushing and the writer to be quite distinct 

 from the typical Lowville beds and separated from them by an un- 

 conformity. It has for that reason been here distinguished as a 

 subdivision under the name Leray limestone and will be described 

 separately [see below]. 



It appears that in this region the Lowville beds beneath the Leray 

 member can be conveniently divided into an upper and lower divi- 

 sion of nearly equal thickness, the upper division alone containing 

 the abundant Tetradium cellulosum and larger Phytop- 

 sis, as well as the typical massive dove limestone strata, while in 

 the lower division more dark or black subscrystalline limestones 

 containing only smaller forms of Tetradium and Phytopsis and 

 more thin bedded dove limestones abound. 



In this lower division also two or more horizons of Stromato- 

 cerium can be observed, which give the beds a very irregular con- 

 cretionary appearance. These horizons are well seen in the rail- 

 road cut just south of Sanford Center, also where the road crosses 



