32 NEW YORK STATE MUSEUM 



zone between the Trenton limestone below and the Utica shale 

 above. The limestone bands range from 3 to 18 inches in thick- 

 ness, and the rock is hard and brittle and quite like the dark blue 

 beds of the Trenton. The shale partings are of blue black shale 

 quite like the Utica above. There is a diminution in amount of 

 limestone and increase in that of shale upward, but on the whole 

 a pretty constant and rapid alternation of the two, continuing 

 through a vertical interval which varies from 25 to 100 feet in 

 thickness, thickest on the west and thinnest on the east. 



Lithologically these beds are no more Trenton than they are 

 Utica but are distinctly intermediate in character, and no more 

 to be classed with the one formation than with the other. There 

 is some little shale in the Trenton below, and some rather calcare- 

 ous beds in the Utica above, but not in sufficient quantity to char- 

 acterize the formation in either case. Whether the contained 

 fossil fauna would ally the transition beds more distinctly with 

 the underlying or the overlying formation, the writer is not quali- 

 fied to determine, though strongly of the opinion that the fauna 

 is equally a transition one. Apparently these beds have been 

 classed with the Utica heretofore. 



Most of the limestone bands of these passage beds are fossilifer- 

 ous only sparingly or not at all, but some contain fossils in con- 

 siderable numbers, and search in the shales will nearly always 

 bring them to light. In the basal portion are some very fossilifer- 

 ous, black limestone bands which seem unmistakably Trenton. 



The best exposures of the Trenton limestone within the map 

 limits are shown in the brooks tributary to West Canada creek 

 from Middleville south. Stony creek, coming in from the east at 

 the county house, shows the best section, comprising the upper 

 portion of the Beekmantown, the entire Lowville which is 15 feet 

 thick here, followed by an unbroken section of 100 feet of Trenton. 

 For ^ mile the fall of the creek is very rapid and most of the 

 section is comprised within that limit. Above, the stream is 

 flowing down the dip for the most part, and the rock thickness 

 passed through in the remaining f mile of exposures is not great. 

 The section ends at or near the base of the passage beds, and 



