PALEOZOIC ROCKS OF THE CANTON QUADRANGLE 9 



Ulrich^) to early Ordovician (Canadian^). The Potsdam and 

 Theresa formations are currently referred to the former and the 

 Ogdensburg or upper Beekmantown limestone is a typical repre- 

 sentative of the latter, but there is still some doubt as to the exact 

 position of the intervening two, as explained beyond. Briefly it 

 may be said that the Heuvelton seems linked stratigraphically with 

 the Theresa below, though its few fossils suggest a later age ; while 

 the Bucks Bridge beds are approximately what has been called 

 " Tribes Hill " in Jefferson county and are therefore probably 

 Canadian, though they may prove not to be a unit. 



These Paleozoic formations occupy in general the northern two- 

 fifths of the Canton quadrangle (localities i to 68 of our map) but 

 under a nearly unbroken drift cover so that exposures there are 

 very few. In the southern half of the quadrangle where outcrops 

 are more frequent are also several outliers of the Potsdam sand- 

 stones (localities 69 to 89) resting upon the crystallines, but these 

 sandstones are either absent or thoroughly concealed in the northern 

 belt, so that the sequence between them and the Theresa beds is 

 here interrupted and must be inferred from neighboring areas, 

 where they are found to pass gradually up into the latter without 

 break or unconformity.^ 



Over the northern area the general attitude of the beds is nearly 

 horizontal, with dips averaging i or 2 degrees and seldom exceed- 

 ing 4 or 5, though a dip of 12 degrees has been measured; but these 

 dips are in all directions and continually changing. They thus 

 indicate a series of gentle undulations of irregular character, low, 

 pitching folds and domes, which it becomes practically impossible 



Saratogan epoch {Potsdam, Theresa and 



Little Falls) 

 Ordovician period: Canadian epoch {Tribes Hill, Beekman- 

 town and Chazy) 

 Mohawkian epoch (Black River and 



Trenton) 

 Cincinnatian epoch 

 Silurian period 

 Devonian period 

 Carboniferous period 

 Mesozoic time (Triassic, Jurassic and Cretaceous). 

 Cenozoic time (Tertiary, Glacial, Postglacial and Recent). 

 But Doctor Ulrich proposes to insert an Ozarkian period between the 

 Cambrian and Ordovician, and to refer to it our Saratogan rocks. He also 

 considers the Canadian, exclusive of the Chazy, as a distinct period. See next 

 footnote. ,. \^\ 



^ Geol. Soc. of Amer. Bui. 22, p. 627, 647. 

 = N. Y. State Mus. Bui. 145, P- 66. 



