42 NEW YOEK STATE MUSEUM 



the extension of the Hoyt lies to the east and south of Saratoga, 

 buried from sight beneath the younger rocks which cover it in those 

 directions. The waters were clearer, less subject to incursions of 

 sand, Cryptozoon reefs flourished as they did not in the normal 

 Theresa, and trilobites and gastropods lived on the surface of the 

 reefs, where we find their fossil remains abundantly today. 



To the thickness of the Hoyt limestone as here measured there 

 needs to be added an unknown amount which we estimate as prob- 

 ably not over 25 feet, in order to reach the summit of the 

 formation. 



From the Hoyt limestone we collected the following fauna: 

 Cryptozoon proliferum, Lingulella (Lingule- 

 pis) acuminata, Triblidium cornutaforme, 

 Matherella saratogensis, (Murchisonia) sp. 

 indet., Matthewia variabilis, Pelagiella hoyti, 

 P. minutissima, Agraulos saratogensis, Lon- 

 chocephalus calciferus, Dicellocephalus 



hartti.D.tribiilis. 



LITTLE FALLS DOLOMITE 



General statement. The name " Calciferous " was originally 

 applied to the considerable thickness of dolomitic rocks which over- 

 lies the Potsdam sandstone in the Champlain and Mohawk valleys. 

 Later on Clarke and Schuchert replaced this by the name Beekman- 

 town, and to the rather unfossiliferous phase of the formation in 

 the Mohawk valley gave the local name of Little Falls dolomite. 

 Brainard and Seely were the first carefully to measure and sub- 

 divide the formation in the Champlain valley, making five subdi- 

 visions which they lettered from A to E.^ Recent work of Ulrich, 

 Ruedemann and Cushing showed that the Little Falls dolomite of 

 the Mohawk valley was the equivalent of division A and the lower 

 part of division B of the Champlain Beekmantown, and that divi- 

 sions C, D and E were absent along the Mohawk ; furthermore 

 that an unconformity everywhere separated the Little Falls from 

 the overlying Beekmantown, and that the natural affiliations of the 

 former were with the Potsdam and Theresa beneath, rather than 

 with the Beekmantown above, both structurally and faunally.^ In 

 the Saratoga region the Little Falls is present and the Beekman- 

 town wholly absent. The lowest division of the Beekmantown, 



lAm. Mus. Nat. Hist. Bui. 3, p. i. 



2 N. Y, State Mus. Bui. 140, p. 97-140. 



