[MATOHEw] STUDIES ON CAMBRIAN FAUNAS 19S 



actively against Mr. Walcott'8 reference of this fauna to a position below 

 that of Paradoxides. 



In November, 1861, Mr. E. Billings published descriptions of the 

 Primordial fossils referred to above, and they were subsequently reprinted 

 in the first volume of his Palaeozoic Fossils under the caption : 



" On some new or little known species of Lower Silurian Fossils from 

 the Potsdam Group (Primordial "). 



" The fossiliferous rocks on the north shore of the Straits of Belle 

 Isle, from which a portion of the species hereinafter described wei-e pro- 

 cured, consist of the following in descending order : 



" 1. Limestones. — Eeddish and greenish-colored limestones, varying 

 in some places to grey, with some red and green shale (Fossils are men- 

 tioned). Thickness, 141 feet. 



" 2. Sandstones. — Grey, red and reddish grey sandstones, the lower 

 beds with pebbles of white quartz. Thickness, 231 feet. 



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

 be of the age of the Potsdam (rroup. 



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

 miles east of Phillipsburg, in the County of Missisquoi, and extends south 

 into the State of Vermont, where it is largelj^ developed, and constitutes 

 the red 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 

 immediate neighborhood in Vermont. At one of these, l^ miles east of 

 S wanton, a number of species have been found by Rev. J. B. Perry and 

 Dr. G. M. Hall, of that town." (Other particulars are given.) 



Bathyuriscus, Meek. 



One of the most noticeable of the genera of the fauna described by 

 Billings is Bathyuriscus, Meek, which the former palaeontologist described 

 under the head of Bathyurus, but as Bathyurus is an Ordovician genus, 

 and the type of the genus is quite different from this trilobite, the generic 

 name given by Meek is preferable. The genus was based on a trilobite 

 found by Meek in Montana, and extended by Walcott to some species 

 found in Nevada. It does not difi'er greatly either in the head or pygi- 

 dium from Angelin's Dolichometopus, but may be distinguished by the 

 higher relief of the head-shield and the more distinctly marked furrows 

 of the glabella. The distinction is no greater than that between the more 

 vaulted and the flatter species of Agraulos (Arionellus) ; it is, therefore, 

 thought to be a sub-genus of Dolichometopus. 



