410 NEW YORK STlTE MUSEUM 



Such conditions everywhere characterize the country along 

 Lake Champlain, Wherever any bit of it has been miapped in 

 detail, one or more faults are sure to be disclosed. They consti- 

 tute the most prominent and characteristic structural feature of 

 the region. 



The faults of the Mohawk valley have been most carefully 

 studied and described by Darton.^ They are inferior to the 

 greater Champlain faults in number and in size, and the numerous 

 cross faults which chairacterize that region are less manifest or 

 are Hacking here, the faults all having a north to northeast trend, 

 with rude parallelism. Four large faults only, crosis the Mohawk 

 valley, the Hoffman, Noses, St Johnsville and Little Falls faults, 

 [pi. 14] though there are several minor ones of less magnitude and 

 extent. Others occur to the northeastward in the Saratoga 

 region, and there must be still others which remain yet undis- 

 covered. 



None of these faults have been traced to any distance on the 

 south side of the Mohawk valley, and it is not certain whether 

 they disappear there, owing to dying out, whether they are there 

 but are difficult to trace, owing to unfavorable conditions, or 

 whether they apparently disappear because the overlying Upper 

 Siluric and Devonic rocks were not affected by them. The 

 matter is of impiortance as giving evidence of the date at which 

 the faulting took place. So far no rocks younger than the Utica 

 and Lorraine shales are known to be involved. If it could be 

 shown that the younger rocks to the south of the valley were also 

 affected, the probability of their Carboniferous age wooild be much 

 strengthened, or at least any correlation of their date with that 

 of the Taconic disturbanice would be rendered impossible. 



The only one of these great Mohawk faults with which the 

 writer is on terms of intimacy is the Little Falls fault. With the 

 remainder he has but passing acquaintance. According to Darton 

 all aire normal faults with neiarly vertical hade, and all down- 

 throw to the east, with the single exception of the comparatively 

 small Dolgeville fault. The throw of the Little Falls fault, where 

 it crosses the Mohawk, is not far from 800 feet, and it maintains 

 approximately the same throw for several miles to the northward. 

 The St Johnsville fault has branched and is fast diminishing in 



^14th An. Rep't State Geo]. 1894. p.33-54. 



