370 NEW YORK STxVTE INIUSEUM 



Returning to the south side, Prosser's sections through the 

 Mohawk valley/ together with the supplementary ones of the 

 writer about Little Falls, are sufficient to show well the bulk and 

 distribution of the formation there. Along East and West Can- 

 ada creeks the thickness is beitween 20 feet and 25 feet, beneath 

 which, in most places, there is a gTadation into the Beekmantown 

 below through a series of passage beds of intermediate composi- 

 tion and appearance, which have about the same thickness as the 

 Lowville itself. In the district between the t^^o creeks the forma- 

 tion has the same general character though locally the passage 

 beds are lacking and the formation thins. At Caniajoharie, 17 

 miles doAA'Ti the river from Little Falls, the Lowville is absent, the 

 unconformity at that horizon being more plainly marked here 

 than at any other locality. Three miles beyond, about Spraker, 

 the conditions are the same. At Tribes Hill, halfway between 

 Fonda and Amsterdam, and 13 miles below Spraker, the Lowville 

 has reappeared, though no complete section of it has been pub- 

 lished, and the passage beds at the base aire lacking. About 

 Amsterdam and Hoffman the formation is usually present but 

 very thin, not exceeding 8 feet, seldom reaching 5, and often 

 falling to 2 feet, showing much variation over short intervals and 

 sharply separated from the Beekmantown. East and northeast 

 from this point it is usually absent though occaisionally seen, and 

 the last reported occurrence seems to be that near Saratoga, where 

 the thickness is but 2 feet. In this neighborhood the Beekman- 

 town is also very thin, apparently marking the place where the 

 rising of the land during Beekmantown times was first felt, and 

 where the separation of the Champlain and Mohawk Beekman- 

 town basins was first effected. 



The prominent features brought out by these sections are : the 

 resting of the Lowville on the Precambric along the western 

 Slide of the region, the conspicuous unconformity at Canajoharie, 

 the passage beds to the Beekmantown in the West Canada creek 

 region and the great irregularity of the formation eastward from 

 there, with its final disappearance about Saratoga. It is as 

 plainly confined to the south and west sides of the region as the 

 Chazy and Oassin are to the east side; and was thus deposited in 



^15tli An. Rep't State Geol. p.619-59. and N. Y. State Mus. Bui. 34. 



