384 NEW YORK STATE MUSEUM 



great, and also that it dimanis]ie& somewhat westwardly, so that 

 it has but little over half the thickness about Utica that it has 

 in eastern Montgomery county. 



North and west from Little Falls, it will be remembered that 

 the Trenton thickens, rapidly and suddenly, and it is of interest 

 to note the coincident thinning of the Utica. Commencing at the 

 north, Walcott's measured section along Sandy creek, in Jefferson 

 county, shows the Utica to be 180 feet thick, with an additional 

 100 feet of passage beds to the liorraine shales above.^ In Oswego 

 county Orton reports, at Central Square 729 feet of shales 

 (Pulaski and Utica) between the Oswego sandstone and the Tren- 

 ton, of which 150 feet are ascribed to the Utica; at Oswego 597 

 feet of shales in the same interval; at Stillwater 643 feet, of 

 which 113 are thought to belong to the Utica; about Pulaski 300 

 feet to 500 feet of shales, of which 100 feet to 250 feet represent 

 the Utica thickness; and at Sandy Creek (Oswego, not Jefferson 

 .county), 250 feet to 300 feet of Utica.^ These are vastly thinner 

 than the Mohawk sections and overlie in general from 450 feet 

 to 650 feet of Trenton, usually in a definite inverse ratio, a strong 

 indication of the contemporaneity of the upper Trenton and 

 lower Utica in the contrasted districts. Moreover, Prosser shows 

 1020 feet of shales in the Vernon well, of which 300 feet are 

 Utica, overlying 350 feet of Trenton ; 873 feet in the Chittenango 

 well, of which 233 feet are Utioa, overlying 60 feet of passage beds 

 and some 600 feet of Trenton ; 505 feet at Baldwinsville, north of 

 Syracuse, the amount to be attributed to the Utica not being 

 stated ; and at Auburn 557 feet of shales, the drill resting in the 

 Trenton 240 feet below its summit.^ These show definite Trenton 

 thickening, and Utica thinning westward, though the change is 

 more gradual than it is to the north. 



Lorraine formation. While no paleozoic rocks younger than the 

 Utica shale are found in sufficient proximdty to the Adirondack 

 region to justify any detailed discussion of them in a consider- 

 ation of Adirondack rocks, yet some of them are sufficiently in- 

 volved with its past history, as will appear beyond, to deserve 

 some notice. 



^Op. eit. p.348. 



^N.Y. State Mus. Bui. 30, p.456, 449, 442, 437. 

 ^Am. Geol. 25:152, 161. 



