650 E. O. ULRICH REVISION OF THE PALEOZOIC SYSTEMS 



not observed, it was to be expected that the whole series of magnesian 

 limestones in the Champlain Valley would be thrown together and cor- 

 related with the Calciferous of the Mohawk Valley. Still, despite the 

 magnitude of the eliminations, the nucleus of the Canadian is now, as 

 it has always been, the limestones in the Champlain-Saint Lawrence 

 region containing the Beekmantown fauna. The elimination of the 

 Chazyan and Ozarkian formations originally included on evidence now 

 regarded as misinterpreted does not exceed the bounds of legitimate 

 emendation. Such changes are demanded by progress. In the present 

 case it is gratifying to note that they do not alter Dana's original con- 

 ception of his Canadian in any really essential respect. The only change 

 of consequence is that the term is now given a higher rank, but this also 

 is a legitimate amendment. 



The term Beekmantown limestone. — The typical Calciferous outcrops 

 being in the Mohawk Valley, and the formation there, as said, mostly 

 Ozarkian in age, the term Beekmantown, which is based primarily on 

 the fossiliferous Canadian rocks of the Champlain Valley, is not, as 

 was believed, exactly equivalent to the lithologic term Calciferous in 

 stratigraphic nomenclature. Strictly speaking, the Beekmantown, con- 

 sidered as a formation, should be determined by the beds found out- 

 cropping at the locality from which the name is taken. Brainerd and 

 Seely's Calciferous Divisions C, D, and E are represented at and in 

 the immediate vicinity of Beekmantown. Division B possibly also comes 

 to the surface in that neighborhood, but Division A, so far as I can learn, 

 has not been seen there. Probably nine-tenths of the fossils regarded as' 

 characteristic of the Beekmantown come from Division D. A few of 

 these occur in the underlying Division C, but none found in C, D, or E 

 crosses the line into Divisions A and B. The faunal break between B 

 and C, therefore, is complete. The unconformable stratigraphic rela- 

 tions between the two divisions, as observed in the vicinity of Ticon- 

 deroga, emphasizes the importance of the break. The unconformity is 

 rendered the more apparent by overlap extinction of a fine-grained lime- 

 stone which is sometimes included by Brainerd and Seely in Division, B. 

 This basal member of the Canadian seems to be entirely absent in the 

 Fort Ticonderoga section. 



The boundary between Divisions B and C being of great importance, 

 and as the lower two beds (A and B) do not show in the typical section 

 of the Beekmantown, it seems unwise, not to say unwarrantable, to 

 include them with the typical members of the formation. Viewed solely 

 from the standpoint of the lithologist, the desirability of distinguishing 



