28 Geology, Sc. of the Connecticut. 
FS, Coal Formation. 
Since the publication # ye description of this series of 
rocks along the Connecticut, I have had an opportunity to 
eXamine more extensively ve I had done before, the coal 
formation of Rhode-Island ; and thus to. institute a com- 
parison between the two. And I feel satisfied that they are 
very distinct from each other ; and that the Rhode-Island 
pre is the oldest. ‘There is a sort of general differ- 
tween them, which is readily recognized by the eye, 
vet which it is not easy to describe. In ‘the Rhode-Islan 
rocks, however, there is agreater resemblance, in the eed 
ral aspect and in the fracture, to primitive rocks than in 
those of the Connecticut ; and the former are, in general, 
harder and more compact than the latter; and their cement 
is more argillaceous. The coarse puddingstone, so ubun-~ 
dant in Roxbury, Dorchester, &c. and which is seen at in- 
tervals inost of the distance to the anthracite beds in Ports- 
mouth, approaches, in certain a very neara a 
rock ds Meuaares ‘Sunderland, Durham, &c. To th 
pow rock, however, the cement is. rate more aes 
the rock, as Maclure very happily expresses it, ‘ has 
the ganas as if the cement at the time of formation 
ry. 
Both omy are transition; yet dia one may gts claim to 
a greater age than the other. 
so momen class (of Werner) for one which could lead to an opposite 
—tbat i is with the facta | clasts | pad. also “ that the sandstones 
pn 
viously mechanical varieties of ereywacke, and ; ietely po 
into that rock, that in maw , ra indent 0 se cep 
a2) ‘transition caine ean only. be abr eon assigned, Kam oy He} ee and 
