32 Geology^ tj^c. of the Connecticut. 



haps the newest floetz trap when it happens to cover the 

 primitive." (Journal of Sci. Vol. 1. p. 212.) Yet there are 

 two circumstances in regard to the rock here denominated 

 primitive greenstone, along the Connecticut, which have led 

 me to doubt its exact indentity with our newest floetz trap, 

 or secondary greenstone. 1. The primitive greenstone is 

 never amygdaloidal; while a great part of the secondary is 

 so. 2. The primitive greenstone not merely covers other 

 rocks, but forms beds in them. An example of this may 

 be seen one mile east of the Milford marble quarry on what 

 is called the old road leading to New-Haven ; where the 

 greenstone lies between strata of a rich intermediate, between 

 greenstone slate and mica slate, and the rocks have every 

 appearance of being contemporaneous. 



Primitive greenstone is colored in the following places on 

 the map, viz. at West-Haven and Milford — at Wolcott — at 

 Whately, in the western part of Northfield and north part 

 of Gill. In regard to that in Wolcott, or the Eastern part 

 of Waterbury, I know but little, it being several years since 

 I observed it, and some snow being on the ground at the 

 time. J put it down merely for the sake of pointing out its 

 locality. 



The most extensive deposit of the rock is at West Haven 

 and Milford ; on both sides, but especially on the east side, 

 of the Verd Antique stratum. The hummocks of it that 

 appear very frequently, but irregularly, very much re- 

 semble the detached hills of secondary greenstone, except 

 that they are less elevated and the blocks of debris are usual- 

 ly larger. A httle south of the Derby turnpike, this is the 

 first rock that shows itself as we ascend from the alluvial 

 plain of New-Haven on the Humphreysville turnpike alsoy 

 there is but a narrow stratum of chlorite slate separating it 

 from the alluvion. 



This greenstone often becomes stratified on both sides of 

 the vidge, forming greenstone slate. At first, we perceive 

 a partial and interrupted stratification ; and in a few feet it 

 becomes decided, extending through the whole mass. 

 There is also frequently seen a double stratification; one set 

 of planes crossing the other rectangularly or obliquely. Well 

 characterized greenstone slate, however, is not abundant in 

 Milford or West Haven. It usually soon passes into chlo- 

 ritic slate, or even into a bastard mica slate. An account of 



