﻿90 NEW YORK STATE MUSEUM 



Leray limestone and reaches to the base of the Trenton. The con- 

 tact with the typical Lowville beds is shown on the opposite side of 

 the river and on Diamond island. Plate 24 shows a part of the 

 quarry. 



Section at Klock's quarry, Watertown 



V/2-2' Black, _ knotty, impure, dark limestone with Strophomena 

 filitexta, Leperditia fabulites, Orthis per- 

 vetus, Isotelus platycephalus, Orthis tri- 

 cenaria, Illaenus a, mericanus, etc. 



7' 7 foot tier. Heavy black limestone, with Gonioceras 



anceps, Hormoceras tenuifilum 



6' Dark gray to black, heavily bedded, cross-striated limestone with 



a few cherts, containing also Endoceras, Gonioceras. Resting on 

 an irregular surface; base of Watertown limestone 



2'-2^2 /A Irregularly bedded, dark to black, dove colored, fine grained lime- 

 stone, characterized by weathered, fucoid, earthy markings 



5'+ Fine grained dark gray limestone, with cherty layer on top. Cherty 



beds. Bottom not shown 



These chert beds are in this neighborhood underlain by 4-5 feet of 

 fine grained dark gray beds with Tetradium cellulosum, 

 which also weather blocky like the Watertown limestone. Below 

 this are found the dove colored, thinner bedded, typical Tetradium 

 beds. 



A series of good sections of the Watertown-Leray limestone are 

 exposed in the large quarries about Chaumont. Since, however, the 

 Seven foot tier forms here the top of the section and an unknown 

 thickness of the same is always eroded, the thicknesses obtained are 

 always a minimum. In the large quarries at the head of Chau- 

 mont bay the combined beds measure 18 feet; in the big quarries 

 along Chaumont river 19 feet of these limestones are found, below 

 which 22 feet of typical Lowville beds are exposed to the river edge. 



Trenton limestone. The last of the Lower Siluric stages oc- 

 curring in the area of the map is the Trenton limestone. It ap- 

 pears first in outliers near the mouth of Black river, then occupies 

 the southern portions of the peninsulas jutting out into Lake On- 

 tario and finally on the Cape Vincent sheet forms a continuous 

 belt. In contrast to the underlying formations and notably its direct 

 predecessor, the Watertown limestone, which forms a remarkably 

 level plateau with a distinct escarpment at the northern boundary, 

 the Trenton appears in well rounded hills, its boundaries approach 

 subcircular curves, in contrast t'o the many fingered and deeply in- 

 dented Watertown exposures. This is due to the fact that the 

 Trenton is a much thicker and at the same time a much less re- 

 sistant formation, consisting almost entirely of thin bedded lime- 

 stones with shaly intercalations. It is therefore also much more 

 covered by drift and as a rule exposed only along the shore line or 



