GEOLOGICAL SUEVEY OF CANADA. 



PALEOZOIC FOSSILS. 



Nov. 1861.* 



I. On some neiv or little-known species of Lower Silurian Fossils from 

 the Potsdam Group (Primordial Zone). By E. BILLINGS, F.G.S. 



The fossiliferous .rocks on the north shore of the Straits of Belle Isle, 

 from which a portion of the species hereinafter described were procured, 

 consist of the following in descending order : 



1. LIMESTONES. Reddish and greenish-coloured limestone, varying in some places to 

 grey, with some red and- green shale. The fossils are Palceophycus incipiens, Jlrcheo- 

 cyathus Atlanticus, Ji. profundus, Obolus Labradoricus, Obolclla chromatica, O. ? tin- 

 gulata, Olenellus Vermontana, O. Thompsoni, Conocephalites miser, Bathyurus parvulus, 

 B. senectusj Salterella rugosa, S. pulchella, and S. obtusa. There are, besides these, two 

 species of Orthis and one of Orthisina, and numerous fragments of trilobites, apparently 

 of several undescribed forms. The thickness of these limestones is 141 feet. 



2. SANDSTONES. Grey, red and reddish-grey sandstones, the lower beds holding peb- 

 bles of white quartz from the size of a pea to one or two pounds in weight. The only 

 fossil observed is Scolithus linearis. Thickness 231 feet. 



These rocks rest upon the Laurentian, and their fossils show them to be 

 of the age of the Potsdam group. They were examined by Mr. J. Rich- 

 ardson during the past summer. 



Another exposure of rocks of the same age occurs about three miles 

 east of Phillipsburgh in the County of Missisquoi, and extends south into 

 the State of Vermont, where it is largely developed, and constitutes the 

 Bed sandrock of the geologists of that state. During several visits made 

 to this exposure last summer, I could find no fossils on the Canadian side 

 of the boundary-line, but several important localities occur in the imme- 

 diate neighbourhood in Vermont. At one of these, 1J- mile east of 

 Swanton, a number of species have been found by the Rev. J. B. 

 Perry and Dr. Gr. M. Hall of that town. These gentlemen are engaged 

 in making a careful geological examination of the rocks and fossils of 



* The following twenty-four pages were reprinted in 1864. See Preface. 



