390 E. Hitchcock on the Metamorphism of 
they will visit and study the localities we have pointed out. 
We have indeed, specimens from them ail, in the Amherst Cab- 
inets, to the amount of several hundred pounds, and they illus- 
trate "nearly all the points we have brought out. But we advise 
gentlemen not to substitute an inspection of find for the more 
satisfactory exhibitions in the mountains. 
Amherst College, Nov. 1, 1860, 
Nore.—A brief and imperfect ascuead of the preceding facts 
and arguments having been presente oy me last autumn before 
the Boston Natural History Sety. Tr. share os ——— 
who presided at the meeting, expressed his diss 
views as to the manner in which the pebbles had can flattened 
and distorted, and his conviction that eae had either been worn 
into these shapes by water, previous to aggregation, or that 
some of these were concretions. At a subsequent meeting, 
Prof. Wm. B. Rogers expressed similar views, which appeared 
in the published proceedings of the society.* I do not under- © 
stand these distinguished geologists to have made up their minds 
very decidedly on the subject, especially as they have not visited 
the Vermont localities. But objections suggested by gentlemen 
i ren large geological experience, deserve serious considera- 
i have already stated my objections to the theory which they 
adopt as to the forms of the pebbles. Prof. Rogers suggests as 
an objection to my views, that the pressure which I suppose to 
have flattened and distorted the pebbles, has not produced cleay- 
age. But this conglomerate is not a rock in which cleavage is 
Pin found. It is a foliated, or schistose rock. It has joints in 
it, such as prove very clearly that it was once in a state more or 
less plastic; but these (the most perfect ones oo ces ce 
the lamin at nearly right angles, and could never haye bee 
roduc y pressure. It isa fact, however, that some of the 
arger pelos particularly at their extremities, do show the com- 
mencement of a schistose structure, probably the fest of pres- 
sure. Yet the facts do not require us to suppose the pressure on 
this rock to have been of the most powerful kind. In some cases 
indeed, as at Plymouth, the pebbles are compressed into laminz, 
but in general, : ey are ‘only moderately flattened, and sie oni 
not at all. If only moderately hr such effects could not 
have hore a very enormous for 
Another objection is, that the enieibeasi cs has as distorted on 
fossil Lingulz found in the pebbles on Taunto , and a 
Newport. But I am not aware that the pebbles i in the Ciaplots 
erate of Taunton river, have Sia compressed and os erie 
nor have they been, in but a part of that around Newport. 
_* See under Grotoar in this mmber the remarks of Prof, Rogers. 
