86 TT. S. Hunt on the Geology of Eastern New England. 
skeleton of the Eozoon, instead of being injected by serpentine 
or another silicate, is simply filled with impure calcareous and 
eee oiicebue matter. ‘The presence of this fossil serves to con- 
nect these rocks with the Laurentian system, with which they 
had provisionally been classed, although their lithological dis- 
similarity had long been n oticed, and in 1866 Sir William 
Logan had remarked chieis't resemblance to the mica-slate series 
found near the sources of the Connecticut River (Report Geol. 
Survey, 1866, p. 98). 
Mr. Alex x. Murray’ s report of his explorations in, Newfound- 
land, published in 1866, throws much light on the history of 
the rocks immediately succeeding the Laurentian in that region. 
He found in the great northern peninsula, about the Cloud 
Mountains and Canada Bay, not less than 5400 feet of strata, 
referred by him to the Potsdam group. Of these the lower 2500 
feet consist of bluish-gray slates, holding near the re beds 
which become conglomerate from the presence of quartz peb- 
bles, and are followed by a mass of purplish erhadh toa dio- 
rite, holding epidote and jaspery red iron ore. Then follow 
2000 feet of = ea ge and somewhat micaceous slates, with 
beds of quartzite and of limestone, generally impure. These 
the Potsdam group. To this second division succeeds a third, 
consisting of about 900 feet additional of limestones and slates. 
Somewhat farther southward, at Great and Little Coney Arms, 
the lower half of the above series is not observed, but a succes- 
sion of strata, supposed to represent the upper portion of the 
otsdam, is more particularly described. It consists, at the base, 
of 800 feet of pale bluish- mica-slates, with iron stains, 
‘softer, more finely laminated, and more uniform both in color 
and in texture” than some micaceous strata described by Mr. 
Murray as pee. n the Laurentian in that region. To these 
succeeded 480 feet of similar soft bluish-gray mica-slates, holding 
numerous thin seams of dark colored limestone, and ‘followed 
to be Laurentian gneiss. e relations of Par saad whiti 
iti¢ mica-slates are aes esse but M was 
inclined to regard them a position beneath the 
occupying 
Potsdam group. The Tatter in Canada Bay, is immediately 
followed by the unaltered fossiliferous —* and shales of 
§ 
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* 
