1040 



NEW YORK STATE MUSEUM 



Just below the lowest bed of the Coeymans limestone occurs 

 the upper Stromatopora bed, forming the topmost layer of the 

 Manlius. It averages 3V 2 feet in thickness, varying between 3 

 and 4 feet, and is for the most part made up of masses of 

 stromatoporoids piled one above 

 the other. In weathered sec- 

 tions these masses are well 

 shown, being less readily seen 

 in the fresh section on account 

 of the massiveness of the rock. 

 Sometimes at the edge of the 

 cliff they are weathered out, so 

 that they look like piles of boul- 

 ders. The largest head measured 

 is about iy 2 feet in diameter. 

 The bed immediately above 

 this layer contains Favosites, 

 crinoid joints and Gypidula 

 g a 1 e a t a , and in texture is 

 finely crystalline. This crystal- 

 line matrix frequently extends 

 down between the Stromatop- 

 ora heads, but more frequently the fine mud-rock fills the inter- 

 stices between the masses of hydrocoralline. The lower line of 

 the Stromatopora bed is very irregular, and sometimes a Stroma- 

 topora is embedded in the stratified Manlius below. 



The " Stromatopora " fragments probably all belong to the 

 genus Syringostroma of Nicholson, but their exact determina- 

 tion is a matter of great difficulty on account of their unsatis- 

 factory preservation and it has not been attempted. 



Besides the stromatoporoids, the following fossils character- 

 ize this bed. 



Spirifer vanuxemi Hall 



This species is represented by a few individuals in the upper 

 Stromatopora bed. They agree substantially with the figure 

 ofOrthis plicata given by Vanuxem, which is the char- 

 acteristic Manlius limestone species of eastern New York. The 

 median sinus of the pedicle valve of our specimens is shallow, 



Fig. 4 City quarry, Hudson ; 1, Coey- 

 mans; 2, 4, 6, upper, middle and lower 

 Stromatopora beds; 3, 5, 7, Manlius. 



