.

differs from the rest of the

he numerous joints and fissures by which they are traversed enable the workmen to wedge them out often in considerable lumps. But till has neither crack nor joint; it will not blast, and to pick it t

#

TH BOWLDER-CLAY,

g, Bowlder-Clay; x

n which it is distributed, and its rela

int and projection has been ground off. They are not very large, and they differ in this and other respects from the bowlders found in the other portions of the Drift. These stones in the

.

alled the "bowlder-clay." This is not so tough or hard. The bowlders in

#

(BLACK SHALE),

ape Cod are twenty feet in diameter. One at Whitingham, Vermont, is forty-

.

me material are found wi

rees. At other times the distinction is marked. Some of the stones in the bowlder-clay are furrowed or st

d with the remains of man and other animals. These have all the appearance of being la

efly stated, the co

s the result of violen

e upon an unparalleled and continent

might justly be accepted with hesitation, were not the conception u

are gigantic, the facts they seek to explain are not less so. We are not dealin

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