GEOLOGY OP THE VICINITY OP LITTLE FALLS 53 



Potsdam may be absent because of overlap, in which case it 

 should be present to the south and west, under cover of the Beek- 

 mantown and still later rocks which are at the surface in those 

 directions; or it may be absent because of nondeposition, the 

 subsidence of the region hereabout not having commenced till the 

 close of the Cambrian ; or, lastly, it may be absent as a recogniz- 

 able lithologic formation comparable with the Potsdam sand- 

 stone, for the reason that no sand was brought into the upper 

 Cambrian sea here by currents or by streams, a limestone or a 

 shale or both having been deposited instead. The latter al- 

 ternative can only be determined by the fossils, and in their 

 absence it is impossible to affirm that the basal portion of the 

 Beekmantown may not be of Cambrian age, though it is not 

 probable. 



Such evidence as has been brought to light up to the present, 

 is not sufficient to enable us to pronounce affirmatively in favor 

 of any of the above suppositions. One or the other of them must 

 represent the actual facts of the case. Such evidence as is avail- 

 able comes from the deep wells which have been drilled to the 

 west and northwest of the district. Of these there may be 

 specially mentioned the Remington well at Ilion, less than 3 

 miles west of Herkimer; the Globe mills well at Utica and the 

 Campbell well 3 miles west of Utica; the Rome Brass & Copper 

 Co. well at Rome; and finally the wells in Pulaski and Orwell, 

 Oswego co. 1 These wells were all drilled with churn drills, and 

 the mashed rock fragments produced by this method of drilling 

 are often difficult of proper determination. Had we diamond 

 drill cores from them, the evidence would be all that could be 

 asked. These wells have all begun in, or above, the Utica shale 

 horizon, and have penetrated the entire rock thickness down to, 

 and a varying amount into, the pre-Cambrian. They have gone 

 through the entire rock series here in question, but the fragmental 



1 Prosser, C. S. Am. Geol. ^5:131-44. 



- Geol. Soc. Am. Bui. 4:110-1. 



Walcott, C. L. Am. Ass'n Adv. Sci. Proc. 36:211-12. 

 Orton, Edward. N. Y. State Mus. Bui. 30, p. 426-50. 



