Geology, ^c. of the Connecticut. 41 



and common granite, and rarely gneiss or mica slate. The 

 coloring matter of the rock, in most instances, has pene- 

 trated through these pebbles, giving the granitic nodules 

 the same color as the rock, and the quartz a bluish as- 

 pect. This conglomerate frequently alternates with the 

 sandstone, and one half of the layer of a rock is sometimes 

 sandstone, and the other half conglomerate, no fissure be- 

 ing between them. Generally speaking, however, the 

 puddingstone increases in quantity and coarseness as we 

 ascend a mountain of this rock, and all the upper part of 

 the hill is sometimes composed of it. Probably more than 

 one half of the old red sandstone in the northern part of 

 the range is this conglomerate : yet, as it is evidently a 

 mere variety of the sandstone, it was thought altogeth- 

 er unnecessary to attempt a division by different colors 

 on the map. 



A considerable part of the range of this rock colored 

 on the east side of Connecticut river, is somewhat dif- 

 ferent in its appearance from that I have been describing 

 on the other side. At least, there is one very abundant 

 variety that is not found on the west side. It consists of a 

 fine, siliceous, red sand, adhering together with but very 

 little visible cemei>t. It has, however, an argillaceous 

 odour. The coherence is not as strong as in the coarser 

 sandstone, it being slightly friable. This rock may be seen 

 in place in the southwest corner of Ludlow, and the east 

 part of Long Meadow, Enfield, Somers, Ellington, &:c. ; and 

 it forms a neater and handsomer building stone than any 

 other rock of the sandstone family which I have ever seen. 



A part of this range of red sandstone, east of Connecti- 

 cut river, appears also to be verging towards the sandstone 

 constituting the coal formation Examples of this may be 

 seen at the extensive quarry in Chatham, and also in Mid- 

 dletown — -there seems to be a gradual passage of one 

 rock into the other — and the strata of both these rocks 

 have their dip in such a direction, as to lead one, at first, 

 to conclude that this old red sandstone lies above the coal 

 formation. The dip of both rocks is to the east. It does 

 not follow, however, from this circumstance, alone, that 

 the red sandstone does in fact repose on the other rocks. 

 Thus, let A B be a profile crossing the valley of the Connec- 

 ticut, and exhibiting the strata of old red sandstone, havine 



VoL. VJ.— No. 1. 6 



