44 Geology^ ^re, of the Connecticut. 



13. Secondary Greenstone. Cleavelandi 

 Colored Carmine, or Rose Red. 



To give the ranges of this rock, was one of the princi-* 

 pal objects in constructing the accompanying map* For 

 although it be an anomalous, it is a highly intepesting 

 formation. The high mural precipices that g^Imost uni- 

 versally show their naked faces in the ridges and hil- 

 locks of this rock — the immense quantity of debris that 

 frequently slope up half, or two thirds the distance to 

 their summits — and the thin tuffs of trees that crown their 

 tops, form much of the peculiar scenery of the Connecti- 

 cut. They remind the European of the basaltic and 

 other trap ridges of Scotland, Ireland, Saxony, Auvergne^ 

 Italy, &C4 



in regard to the greenstone* north of Hartford, I feel 

 confident that every range of it to be found in place, is in-' 

 serted on the map. South of Hartford some small and low 

 hillocks of it may have been overlooked, notwithstand- 

 ing all the assistance I have received from Prof. Silliman 

 and Dr. Percival. For, in some places, this rock seems to 

 be but a few feet in thickness above the sandstones, and to 

 he less continuous than in the northern part of the map. 

 In East-Haven and Branford especially, there are so many 

 ridges of greenstone, and these so irregular, that it is diffi- 

 cult, on a map of such a scale, to make them all distinct 

 and accurate.! 



The most southerly point of greenstone on the map is 

 the bluff in East-Haven, which fronts Long Island Sound, 

 and is about one mile and an half north of the Light-House. 

 The most northerly points of this rock are in Gill and in 

 Norlhfield. The greenstone which occurs in the upper 

 part of Northfield, is more crystalline and of a coarser tex- 

 ture than in the intermediate distance, and is undoubtedly 



* To save room, I shall omit, in the remainder of this article, the term 

 secondaryj as applied at the head of the article. 



t There ought to be a geological map of the region about New-Haven, 

 on a larger scale than the one I have given : and we could name more than 

 one gentlemaa in that city, who is amply qualified for its construction. 



