48 



lower portion of the mass in the same position, and with the 

 same fossils as at Section 5. It alone furnishes the specimens 

 of large Cyathophylloids and Atrvpa aspera Dalman, 

 whicli arc so common in some portions of the talus. The 

 specimens of Streptclasma rectum Hall are likewise fur- 

 nished by beds of the low^er Moscow shale. 



The Styliolina limestone rapidh' thins out towards the 

 south, so that, at the middle of the section, it is vScarcelv an 

 inch in thickness, being at the same time very shal3^ The 

 Genesee shales, in this section, appear in their full thickness, 

 which, according to Professor Hall, is twenty-three feet and 

 seven inches, including the Styliolina band.* The lower 

 portion of this shale is more homogeneous in this section, 

 partaking in color and texture more of the character of the 

 upper beds. The bituminous character of the shale as a 

 whole is strongK' marked, plant remains and even coal 

 seams being of not infrec|uent occurrence. Large masses of 

 the rock are usually found on the beach, and in them the 

 characteristic fossil Lunulicardivm fragile^ Hall, is often 

 found in great numbers. P\-rite grains are scattered 

 throughout the shale in large quantities, and these on 

 oxidizing produce the usual result of thin, iron-stained 

 shale laminae, which frequently have iridescent surfaces. 



One of the interesting products of the oxidation of the 

 pyrite, is found in the sulphuretted water, which trickles 

 from the bank at various places. On exposure to the air, the 

 sulphuretted hydrogen, with which the water is charged, is 

 commonly decomposed, (see below) and sulphur is deposited. 

 This is well seen in a small cavernous indentation in the 

 bank, midway between Eighteen Mile and Pike Creeks, 

 where the shale walls are covered with a thin coating of 

 sulphur. 



*Rep't 4th Geol. Dist. N. Y., 1843, p. 221. 



tThis is the Avicula fragilis Hall of the Geol. Rep't of the 4th Dist., 1843. 



