MINERALS AND GEOLOGY OF CANADA. 123 
tial or local exceptions, the Laurentian area is not favorably circum- 
stanced for agricultural occupation. Soils of depth and fertility can 
only be expected to occur under the following conditions :—first, where 
feldspar rocks or anorthosites prevail, most of these yielding calcareous 
soils by decomposition ; secondly, where the belts of crystalline lime- 
stone crop out and form the surface of the country ; and thirdly, where 
the rocks are covered to a sufficient depth by Drift clays and sands. 
These latter deposits, however, are usually filled in these districts with 
large and numerous boulders, and rarely extend over areas of any con- 
siderable size. Patches of a certain extent occur here and there, but 
they are too generally separated by huge and bare masses of gneissoid 
rock, familiarly known to the settlers as “ elephants backs.’ Such, at 
least, is the general condition of the country in the back townships of 
the western counties mentioned above. Northwards, and in Eastern 
Canada, the severe climatic relations which there prevail, must be 
added to these disadvantages. In those parts of the province, however, 
which are occupied by other rock-formations, numerous uncleared 
tracts of unrivalled fertility are still left to repay the settler’s toil. 
Huronian Series :—The rocks of this group, the next in ascending 
order above the Laurentian series of strata, may be described under 
the following heads:—1, Mineral characters ; 2, Associated intrusive 
rocks; 3, Economic materials; and 4, Topographical distribution.* 
1. Mineral Characters of the Huronian Strata :—These rocks con- 
sist principally of thick beds of quartzite, passing into quartzose and 
jasper conglomerates ; green slate rocks passing into slate conglomer- 
ates ; bands of compact or sub-crystalline limestone ; and interstratified 
masses or beds of greenstone. The entire thickness of the series, 
where fully displayed, is probably not far short of 20,000 feet. The 
quartzites are chiefly white or greenish in colour, but exhibit in some 
places grey, brownish, and also red tints. Some are vitreous in tex- 
ture; others, more or less arenaceous. In the conglomerates, the 
included pebbles, which are sometimes quite small, consist of different 
varieties of quartz—colourless, opaque-white, brown, black, dark-red, 
* It is but just to state, that most of the facts given under these heads. are drawn from 
the publications of the Geological Survey of Canada. The writer, however, has visited the 
north shore of Lake Huron where the rocks of this series are chiefly displayed; and he has 
thus examined many of the strata and greenstone masses iz situ, and has procured, persons 
ally, a considerable collection of specimens from that locality. He is consequently better 
able than a mere compiler would be, to classify and separate from subordinate details the 
more salient points belonging to the study of this geological group. These observations will 
apply also to other cases in which he is more especially indebted to the labours of the Survey 
