﻿GEOLOGY OF THOUSAND ISLANDS REGION 83 



Unfortunately no good sections were found in the northwestern 

 portion of the area, permitting a comparison with that of Lowville 

 as to thickness and arrangement of horizons. 



Section at railroad bridge at Lowville (type section) 

 Lowville section 



6' Cherty beds. Dark blue, finely granular limestone, dirty white 



weathering. Columnaria horizon at base 



1' 6" Bed full of horizontal worm tubes. Chert horizon at base 



5' 9" Transitional bed from Leray to typical Lowville. In aspect like 

 cherty beds with a few cherts, but contains also Tetradium 

 c e 1 1 u 1 o s u m , besides Leperditda fabulites, 

 Rafinesquina minnesotensis, and other brachiopods 

 and bryozoans 

 Base of Leray 



3' Dove limestone, massive. Phytopsis tubulosum com- 



mon near top; a few Tetradium cells 



3' 1" Compact dark dove limestone, full of fossils (Tetradium, gastro- 

 pods, lamellibranchs) and of crystalline calcite 



4' 9" Thin bedded, dove limestone, full of Tetradiums (form with nar- 

 row, round tubes) 

 5" Dark, fine grained impure limestone with argillaceous streaks, 

 containing a small Monticulipora 



2' 4" Lighter, massive bed of dove limestone with few Tetradiums. 

 Lowest 8 inches black, with thin seams of flint 



4"- 7" Stratum of granular, light gray limestone full of lamellibranchs 

 and gastropods, their shells filled with calcite 



1' 3" Black, massive, crystalline limestone, full of Tetradium 

 .3' 4" Black to dark gray thin bedded dove limestone, containing a few 

 Phytopsis 

 4" Same rock as above, but full of a narrow form of Phytopsis 

 4" Black, dove limestone stratum full of crystalline calcite 



1' 7" Dark gray, granular limestone with many calcite crystals. Bottom 

 of quarry 



4' Dark gray, thin bedded, dove limestone, weathering shaly 



4' Harder, argillaceous limestone 



3' Jo" Shaly dove Limestone, varies much, very shaly in middle, full of 

 sand grains, contains a few lamellibranchs 



1' Hard, oolitic blue limestone, full of quartz grains and pebbles 



6"-io" Shaly bed with seams of quartz grains or grit bands 



o- 3'+ Dark bluish gray limestone, full of pebbles, shale below. Very 

 variable in thickness. Unconformity. Base of Lowville 

 • i' 10" Gray and -pinkish granular limestone, dove in parts 

 4" Thin bedded, shaly limestone, sand grains near top 



1' 10" Dove, dark mottled, fine errained limestone, typical upper Pamelia 



1' 7" Dove limestone with argillaceous reticulation, light pink in parts, 

 weathering shaly 

 9" Bluish black flinty dove limestone 



10" Gray, granular limestone with calcite and quartz grains, in parts 

 conglomeratic, a few fossils. (Rafinesquina incras- 

 sat a ) 



i' 5" Light dove limestone, somewhat argillaceous, coarsely laminated. 

 Phytopsis on top 



2' Grayish, bluish, blocky, subgranular limestone 



i' Compact bed of harder, light bluish gray limestone 



1'+ • Dove, light gray limestone with crystalline specks 



