Geology of Seneca County. 99 



120 feet in the bank of Highland creek (" Sixteen-mile creek " of 

 Gibson's map) is an advantageous one, and was attentively 

 scanned, but with negative results. The possibility remains that 

 it exists in the lower layers in the stream-bed, but its presence is 

 not indicated by any falls, in this or other ravines. 



Portage Beds. 



The transition from Genesee to Portage in Tompkins county is 

 effected, according to H. S. Williams (Fossil Faunas of the 

 Upper Devonian, p. 10), by "two thick sandstone layers 

 separated by a few inches of shale, the whole about four feet 

 thick ; in these sands and shales there are great numbers of 

 pyrite nodules from the size of a pea, or smaller, to an inch and 

 over in leng-th. No fossils were observed in these first beds. 

 Following the sandstone are the sandy shales, characteristic of 

 the Portage group," etc. 



The corresponding layers are well shown in the base of the 

 cliff just south of Faucett's Point ; also in the two Lodi glens^ 

 especially the southern one. At Faucett's, the layers in question 

 are covered with water in some stages of the lake, and hence the 

 rock displays chemical erosion, with cavities marking the disap- 

 pearance of pyrite. They comprise a mass of heavy gray and 

 green sandy shale, two feet and more in thickness, which is 

 sometimes compacted in nearly solid courses, and sometimes is 

 indistinguishable from the shale above it. The upper part (one 

 foot or more) was not observed to be fossiliferous. The lower 

 foot varied from point to point ; now consisting of large con- 

 cretions of very tough limestone with pyrite nodules (above 

 noted) ; now embracing considerable masses of small branching 

 coral (cladochonus), which serves to identify the corresponding 

 layers in Lodi glen ; and again, consisting of only a thick bedded, 

 irregular sandy shale. The band here described was traced for 

 1,000 feet north of the Point ; still further north its presence 

 was indicated* by large fallen blocks containing the coral. 



At Lodi the band runs some six to eight feet above the base of 

 the falls. It is diflScult to trace it along the wall of the ravine ; it 

 varies in apparent thickness and becomes merged in the other 

 shales. 



