126 NEW YORK STATE MUSEUM 



Feet Inches 



I Massive, finely crystalline to granular, gray dolomite, 



with large calcite nodules 3 



Interval to surface of Precambric in West Canada 

 creek, about • 50 



In this section, including the concealed , interval at the base, we 

 have a thickness of 231 feet of Little Falls dolomite, as measured 

 from the base of the Lowville down to the level of West Canada 

 creek, which is substantially the base of the formation. There is 

 nothing that we could definitely correlate with the Tribes Hill 

 limestone as already stated. The thickness here is just about half 

 the combined thickness of the two formations at Little Falls. 

 Since .at least 50 feet have gone from the summit it seems to us 

 clear that the thinning in this direction is not due simply to over- 

 lap, but represents a loss both above and beneath ; that is that each 

 of the two formations thins northward, and that the Tribes Hill 

 has thinned to the vanishing point. 



It will also be noted that there is here a thickness of nearly 

 19 feet of Lowville and that the Lowville is directly followed by 

 the Plectambonites and Prasopora bed of the Trenton with no 

 sign of the older beds, which in the Mohawk valley have usually 

 been referred partly to the Black River and partly to the Trenton. 



Four miles northwest of Middleville along West Canada creek 

 is Newport, and here the most westerly of the good sections, 

 exposing the horizon with which we are especially concerned, is 

 found. The exposures are in the creek bed, the railroad cut just 

 south of the depot and in Dunn's quarry a few rods west of the 

 depot. 



SECTION AT NEWPORT 



Feet Inches 



12 Crystalline, highly fossiliferous, gray limestone-bands 

 alternating with black argillaceous nodular lime- 

 stone and a little shale, Plectambonites very abund- 

 ant ; basal Trenton . 2 6 



Hiatus 



11 Blocky, nodular, fine grained limestone, black lime- 

 stone containing Columnaria and Streptelasma ; 

 • has heretofore been referred to as " Black River " 

 but represents the Leray limestone member of the 

 Lowville formation in Jefferson county 2 2 



Small hiatus 



