KEW YORK BTATE MUSEUM 



ialand , talline rocks, the beda are little disturbed and some- 



timea highly fossiliferous. The Birdseye rarely exceeds 6 feet 

 i„ thickness. i\ ia a pure dove colored to .lark -ray limestone 

 with conchoidal fracture and often containing veins of quartz or 



calcite. 



The total thickness of the Trenton in the Champlain valley is 



, n ,l it overliea the Chazy. Quarriea have been opened 



ap at [ale La A£otte, Plattsburg, Larrabees point, and Crown 



point. 



The Black river limestone in the Champlain valley is locally 

 known La Motte marble. It has a varying thickness from 



Larrabeea point to 75 feet on Crown point and 20 feet 

 Plattsburg. The stone is usually heavy bedded, tough, com- 

 pact and black. 



The Trenton proper is exposed at Crown Point (K Y.) where 

 it haa a thicknesa of 150 feet. It is usually thin bedded and 

 Bhaly but containa several beds of purer limestone. 



Beginning at a point about one half mile south of Smiths 

 Basin in Washington county, the Trenton limestone extends 

 northward, passing east of North Granville, east of Whitehall, 

 which lies on the western edge of the belt, then northward in a 

 belt from one mile to half a mile wide, past Benaon Landing and 

 northward into Vermont. The town of Vergennes lies on the 

 stem border of the belt. Another belt of this same rock is 

 found farther Bouth in Waahington county, extending from a 

 point half a mile north of Easton Cornera up to and for half a 

 mile north of Argyle. Throughout its extent the rocks of theae 

 two more or leaa continuoua belt- have been highly disturbed by 

 dynamic forces. They are much folded and crushed ami at times 

 aaaume a very Blaty structure. The limestone is generally fine 

 grained and of a black color, La traveraed by numeroua veins of 

 white calcite and is frequently of high purity. It is mined at 

 Smiths Basin and also wesl of Fairbaven on the Vermont line. 

 At both of these localities the stone has been quarried for lime- 

 making and flux. 



