relations of the Metamorphic Rocks. 223 
3. In the third place, there is a great series of crystalline schists, 
which are in Canada referred to the Quebec group, an inferior 
part of the Lower Silurian system. They appear to correspond, 
both lithologically and stratigraphically, with the Schistose group 
of the Primitive slate formation of Norway, as recognized 
Naumann and Keilhau, and to be there represented by the strata 
in the vicinity of Drontheim, and those of the Dofrefeld. The Hu- 
ronian series of Canada in like manner appears to correspond to 
the Quartzose group of the same Primitive Slate formation. It 
consists of sandstones, imperfect varieties of gneiss, diorites, sili- 
cious and feldspathic schists, passing into argillites, with lime- 
stones, and great beds of hematite. Though more recent than 
the Laurentian and Labrador series, these strata are older than 
the Quebec group; yet, from their position to the westward of 
Series. 
altogether wanti ng, extremely rare in the Laurentian system, 
The aluminous sediments of the second class are, however, repre- 
Sented in this system by a diabase made up of dark green py- 
Toxene iddbiciale 
mo-ferrous garnet. This es constitutes 
