1870.] HUNT — ON GEOLOGY OF EASTERN NEW ENGLAND, 201 



limestones of the Trenton group. This intermediate series, 

 which attains a thickness of several thousand feet, is terminated 

 by calcareo-micaceous schists, in which Eozoon Canadense has 

 been found, both in Madoc and in Tudor. In these localities, 

 as shown by Dawson and Carpenter (Sill. Jour.. II., xlviv, 3G7), 

 the calcareous skeleton of the Eozoon, insttal of being injected by 

 serpentine or another silicate^ is simply filled with impure calca- 

 reous and carbonaceous matter. The presence of this fossil serves 

 to connect these rocks with the Laureutiau system, with which 

 they had provisionally been classed, although their lithological 

 dissimilarity had long been noticed, and in 186G Sir William 

 Logan had remarked their resemblance to the mica-slate series 

 found near the sources of the Connecticut Eiver (Report Geol. 

 Survey, 1866, p. 93). 



Mr. Alex. 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 Clouds 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 summit, beds which become 

 conglomerate from the presence of quartz pebbles, and are follow- 

 ed by a mass of purplish amygdaloidal diorite, holding epidote 

 and jaspery red iron ore. Then follow 2000 feet of argillaceous 

 and somewhat micaceous slates with beds of quartzite and of 

 limestone, generally impure. These contain, besides numerous 

 fucoidal markings, the remains of a Lingula, and of Olendlus 

 Vermontanus, a fossil characteristic of 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 succession of strata, supposed to 

 represent the upper portion of the Potsdam, is more particularly 

 described. It consists, at the base, of 300 feet of pale bluish- 

 gray mica-slates, with iron stains, '' softer more finely laminated, 

 and more uniform both in colour and in texture" than some 

 micaceous strata described by Mr. Murray as occuring in the 

 Laurentian in that region. To these succeeded 430 feet of sim- 

 ilar soft bluish-gray mica-slates, holding numerous thin seams of 

 dark colored limestone, and followed by 1000 feet of impure 

 limestones and slates, often micaceous and calcareous, among 

 Vol V. N No. 2. 



