196 Thirty-fifth Eeport on the State Museum, 



West hill ridge is the next in order, and joins with Italy hill in the 

 southern portions of Jerusalem and Italy, forming a large area of high 

 land. Crossing Larzalier's hollow, through which the waters of Lake 

 Keuka once flowed into Kashoug creek, we ascend East hill. This 

 elevation is short, terminating at the north in level lands near the 

 northern boundary of the town of Jerusalem, and in Bluff Point at the 

 south. There is a cutting through this ridge at Branchport to Kin- 

 ney's Corners which divided Bluff Point from the main land and 

 made an island of it when the level of the lake was seventy-five feet 

 higher than at present. From East hill we descend into the valley 

 of another former outlet of Lake Keuka, but more recent than the one 

 through Larzalier's hollow. Between this hollow and Seneca lake is 

 an elevation which terminates in high lands in the town of Barnngton. 



Kock Formations. 

 Chemung Group. 

 The three western ridges are capped with the coarse sandstones and 

 shales of the lower part of the Chemung group. There are no good out- 

 croppings of this rock in the county, but from surface indications it 

 would appear that some of the strata are highly fossiliferous. The 

 coarse white sandstones have yielded us some fine specimens of Die- 

 tyophyto7t tuberosum, Conrad, D. nodosum, Hall, and Lepidodendron 

 corrugalum, Dawson. Associated with these was Equisetides Wright- 

 iana, Dawson, the description and figures of which are copied from the 

 Quarterly Journal of the Geological Society of London for May, 1881. 



Equisetides Wrightiana.* 



Plate XV — Figs. 1-3. 



" This is a specimen from Mr. Wright's collection. It is a cast in 

 sandstone,. six centimetres in diameter, with nodes from four to five 

 centimetres apart. The surface has a slight carbonaceous coating and 

 is finely tuberculated, the tubercles being very regularly arranged, and 

 representing the bases of very short hairs or bristles, which are seen 

 entering the surrounding matrix. Impressions above the joints ap- 

 pear to indicate sheaths, each of about twelve broad leaves, which are 

 abruptly narrowed and acuminate at the top, and show an indication 

 of a median nerve or rib (fig. 10). The leaves of the sheaths are one 

 centimetre broad and one and seven-tenths centimetres long. It would 

 be possible, however, to interpret these supposed sheaths as due to mere 

 plications or foldings of the epidermis ; and in this case the plant may 

 have borne verticils of leaves, of which these supposed sheaths may be 

 merely the remains. The first explanation, however, appears more 



*See note at the end of explanations of figures on Plate XV. 



