184 On the Silurian System of the Lake Superior Region. 
nine miles from the lake, the surface is mainly covered by an ac- 
cumulation of boulders, apparently derived from the drift, which 
into an accumulation of this character; but, above, it again 
to the westward, and lays bare, on the east side, a ledge, some 
twelve feet thick, of grey limestone, thin-bedded, and containing 
small cavities, sometimes lined with crystals of magnesian carbo- 
nate of lime, and at others empty. ‘These layers are a continua 
tion of those before described as occurring at the water’s edge, 
several miles below. 
From this point, onward, for a considerable distance, the dip of 
the strata is more rapid than the descent of the stream, though 
the latter is quite rapid ; consequently, there is a succession of the 
lower strata presented to view in its banks. I had, therefore, an 
opportunity of verifying my first observations, that the grey, gran- 
ular limestone rested upon some shaly and arenaceous beds wit 
thicker calcareous strata, like those seen at the Lower falls, suc- 
are almost constantly in view to the Upper falls, and from thence, 
onward to the forks of the river. About two miles from the up 
per end of the meadow, the Birds-eye limestone is seen at t 
ner, and an examination shows that it is filled with a kind of 
from their commencement, which is very ancient—since two or three were observed 
which had fallen from age—they had stood in the open areas which they now ena 
. In such wooded bottom-lands, in this latitude, we often find plants and trees 
ourishing luxuriantly, which, under ordinary circumstances, are found only more 
southern situations. ‘ 
