66 NEW YORK STATE MUSEUM 



are characterized by patches of black chert, square yards in size. 

 Ai the point northeast of Cole island the beds of division D begin 

 with bluish gray massive limestones, weathering with irregular sur- 

 face owing to the dolomite content. This subdivision D contains 

 also many indistinct sections of Ophileta. The section continues 

 westward to Cole bay, at the northern boundary of which, opposite 

 Cole island D^ characterized by thin, tough, slaty layers of lime- 

 stones is shown. Back of Cole bay in the falls of Stacy brook 

 over lOO feet of division E are finely exposed. They appear as 

 drab to bluish gray magnesian limes ones, regularly divided into 

 one-foot beds with shaly intercalations. The upper beds abound 

 in crinoid joints; otherwise fossils seem to be rare in this locality. 

 South of Cole bay the contact of the Beekmantown and the 

 Chazy can be followed for a long distance. Since here this con- 

 tact, which is rarely seen, is well exposed, we will insert the details 

 of the section, which liave been studied in company with Dr E. O. 

 Ulrich : 



lo' Conglomerate, heavy bedded, crystalline, bluish black 



limestone ( Chazy) with Phylloporina incepta, 

 grading upward into the banded limestone with ]\laclurites. 

 At the base are irregular crystalline 6' layers, full of fos- 

 sils : Phylloporina incepta and numerous ostra- 

 cods, small and larger trilobites, fragments of Orthis c o s - 

 talis and other brachiopods. ]\Iost of the beds (lower 

 half) more or less conglomeratic. Base of Chazy 

 2' Even blue, calcareous shale. Xo fossils 



2' 6" Fine grained^ earthy, mottled, light and darker gray 



bluish impure limestone 

 2' 6" Thin, I'ght bluish shale with thin earthy and sandy lime- 

 stone intercalations. Full of small branching fucoids 

 8' Black, whitish weathering, blocky, impure, barren, bluish 



gray dark limestone with shale partings. Lighter colored, 

 finely granular to every t^mpact. limestone in layers of 3 

 inches to 2 feet 



It will be seen by this section that the lithologic change from the 

 Beekmantown to the Chazy is abrupt. Since the Chazy begins with 

 conglomeratic beds, there is little doubt of an unconformity at its 

 base. 



Another smaller series of outcrops has been observed in the 

 Westport area on the other side of the plain of Champlain clays 

 near the foot of the line of bluffs of Precambric rocks marking the 



