AGE OP MOHAWK VALLEY CALCIFEROUS ?8l 



The upper of the two formations on the Mohawk is a limestone formation, 

 which has heretofore uniformly been described as the "Fucoidal beds" of the 

 Calciferous. It contains a considerable fauna which has been described by 

 Cleland. The authors regard it as of Beekmantown age and as representing 

 the lowest known division of the New York Beekmantown. The fauna has 

 not as yet been recognized in the Champlain Valley, and the formation, if 

 present there, is represented by the upper portion of division B. The authors 

 are proposing for this formation the name of the Tribes Hill limestone, and 

 restrict the name Little Falls dolomite to the lower dolomite formation. 



About Saratoga is a very local representation of a very fossiliferous lime- 

 stone, well known as the source of the Cambrian fauna described by Walcott. 

 This seems to us to be on the horizon of the lower portion of the Little Falls 

 dolomite and to represent a more offshore phase of that formation. 



The authors find everywhere an unconformity at the summit of the Little 

 Falls dolomite, both in the Mohawk and Champlain Valleys. They regard 

 this as the proper boundary between the Saratogan and Beekmantown — be- 

 tween the Cambrian and Ordovician of present-day classification. This gives, 

 in New York at least, a prominent unconformity between the two systems, 

 instead of a gradation of one into the other. 



The complete paper is published in New York State Museum Bulletin 

 140, pages 97-140. 



UPPER GATUQAN OF MARYLAND 

 BY T. POOLE MAYNABD 



(Abstract) 



The upper Cayugan of Maryland occurs in two well defined areas in the 

 western part of the state, the Hancock and Cumberland areas, and crosses the 

 state in a northeast-southwest direction, following the general trend of the 

 Appalachians. The rocks constituting the upper Cayugan consist usually of 

 argillaceous, thin-bedded limestones at the bottom, passing gradually into the 

 heavier-bedded limestones of the lower Helderberg. These limestones lie be- 

 tween the Salina below and the Coeymans above and have an average thickness 

 of 110 feet. There is only a gradual change in lithology from the Salina to 

 the Coeymans and no well defined lithological break exists. The upper and 

 lower limits of the rocks constituting the upper Cayugan are determined on 

 paleontological grounds. These rocks, while equivalent in Maryland to the 

 Manlius and Cobleskill of New York, can not be subdivided in Maryland either 

 on paleontological or lithological grounds. The Rondout is absent in Mary- 

 land, while the fauna of the Cobleskill and Manlius are not distinct and sepa- 

 rate as they are in New York, but they intermingle, typical New York Manlius 

 and Cobleskill forms occurring together. They are also associated with forms 

 occurring in the upper Decker Ferry of New Jersey. 



Discussion 



Prof. A. W. Grabau urged the abandonment of the name Cayugan and the 

 substitution of the term Monroe; also the abandonment of the term Salina as 

 referred to the Maryland section, and the substitution of some other name. 



LIV — Bull. Gbol. Soc. Am., Vol. 21, 1909 



