Handbook of Paleontology 263 



Peter (Lower Ordovician) and Ulrich places it at the base 

 of the Richmond, hence at the base of the Silurian. 



Climate. So far as known at present the climate 

 was uniformly mild and equable, that is, warm tem- 

 perate, throughout the northern hemisphere in both Cana- 

 dian and Ordovician times, as indicated by the vast ac- 

 cumulations of limestones and dolomites, the reef corals 

 of the Middle Ordovician and the fossils found in Arctic 

 lands. 



New York formations. The Beekmantown (Cana- 

 dian) submergence in New York State in general begins 

 with deposition of the Tribes Hill limestone which over- 

 lies the Little Falls dolomite nearly everywhere in the 

 Mohawk valley. As far west as Middleville and New- 

 port it is absent showing that the Little Falls sea here 

 lapped farther north on the Adirondack oldland. The 

 Tribes Hill also does not extend as far north as Sara- 

 toga, and the exact equivalent of the formation has not 

 been found in the Champlain valley. The Tribes Hill 

 submergence had a different pattern than the Little Falls 

 sea, occupying more limited embayments on the south and 

 west side of the Adirondack area, while the latter covered 

 the southern and eastern flanks. The depression in the 

 west lasted only a short time. The uplift following tilted 

 the land to the east giving rise to a long continued sub- 

 mergence in the Champlain valley. The remaining divi- 

 sions of the Beekmantown limestone are confined to this 

 trough with its prolongations north and south and the 

 Ogdensburg area on the northwest side of the Adiron- 

 dacks. A narrow body of water connected with the 

 North Atlantic, called the Levis channel and believed to 

 be distinct from the other seaway, extended from New- 



