78 A List of Minerals and Organic Remains. 
ous, southward over the peninsula included by Lakes Erie, 
Ontario, Simcoe and Huron, although buried under deep 
alluvion; and over Ohio, Michigan, &c. to the Gulf of 
Mexico. ae inn iaes 
The secondary limestone of the St. Lawrence and its 
lakes, is of various colors, chiefly dark and pale blue and 
brown, the latter being sometimes'green, and at others 
passing into a straw yellow, while the former graduates into 
black. Its texture is granular, varying in fineness from 
coarse to extremely compact, and then having a faiut jus- 
tre. The fracture is conchoidal, although, in certain states, 
obscurely. It is always horizontal, except very rarely and 
in minute portions, as at Jacques Cartier, L. C. and at Point 
Henry, U. C. It is divided into layers which are usually 
one or two feet thick, but frequently also ten or fifteen feet. 
It is quite common for the same stratum to subdivide dif- 
ferently in contiguous places. Perpendicular cleavages 
every where show themselves, separating sets of layers into 
rhombic or squared masses. ‘The floor and roof of each 
layer is extremely rough, and coated with a thin black 
glaze, perhaps of clay, which scales off; red clay is fre- 
quently interposed in this manner, as is common in moun- 
tain imestone. ‘The iimestone is usually most massive in 
the upper portions, the lower being slaty, and even shaly, 
black, comparatively free from organic remains, and some- 
times altogether so. ‘The upper strata are also often so 
- crowded with sparry casts of fossils, as to become quite 
crystalline. Where these are more cr less chertzy, the 
compact or granular cement is washed away by rains or 
currents, leaving the casts in high relief. In this form, the 
limestone of Lake Huron, &c. can scarcely be distinguish- 
ed from that of Dudley, in Staffordshire. In all its modi- 
fications, it is occasionally fetid, from the presence of bitu- 
men or sulphur. ‘The limestone now described, abuts on 
one of the older rocks directly, or with the interposition of 
another horizontal stratum; and by far the most commonly 
on gneiss, which I have strong grounds for believing to be 
of the same age and general characters throughout the 
whole of the districts under consideration. It is incumbent 
directly on gneiss in the bed of the river St. Anne, near its 
upper Falls, in the seigniory of St. Feriole, L. C.5 at 
Montmorenci, not far from the “ the natural steps;” but 
