404 Review of the Progress of 
and Silurian gneiss formations, as seen in the Laurentides and 
Adirondacks, and in the Green mountains. The same parallel- 
ism may be extended by Scandinavia, (where Kjerulf and Forbes 
have shown much of the crystalline gneiss to be of Silurian age,) 
marking as it would seem the outer edge of a vast Silurian basin, 
which may be followed in the other direction across the Atlantic 
' to the Gulf of Mexico. We also remark in Great Britain as in 
America, that whereas the northern outcrop of the palzeozoic 
basin offers at its base only a series of quartzose sandstones re- 
posing upon the Laurentian system and characterized by fucoids 
and Scolithus, we find further south in England an immense de- 
velopment of shales, sandstones and conglomerates, which form 
the base of the Silurian system and correspond to the Primordial 
zone and the Quebec group. 
e have said that upon Lake Huron and Superior the sand- 
stones of the upper copper-bearing rocks are the equivalents of 
the Quebee group. The clear exposition of the question by Mr. 
J. D. Whitney in the Mining Journal for 1860 (p. 485) left 
little more to be said, but the sections made last year by Mr. 
Alex. Murray of the Canadian Geological Survey place the mat- 
ter beyond all doubt. On Campment d’Ours, a small island 
near St. Joseph’s, the sandstones of Sault St. Mary are seen re- 
posing horizontally upon the upturned edges of the Huronian 
rocks, and overlaid by limestones which contain in abundance 
the fossils of the Black River and Birdseye divisions. The only 
fossil as yet found in these sandstones is a single Lingula from 
* Murchison, Quar, Jour, Geol. Society, vol. xy, 53 and xvi, 215. 
