GEOLOGY OF THE WESTERN DISTRICTS OF CANADA. 499 
proceed farther east, we find it approach within nine miles. With 
the exception of the Niagara River, no streams of any importance 
empty themselves into Lake Ontario throughout this region, as 
might naturally be expected from the proximity of the ridge to the 
shore ; and that remarkable river itself, as I shall hereafter show 
presents anomalies and peculiarities perhaps nowhere else to be met 
with in nature. 
_ The geological structure of this region is remarkably simple, ex- 
hibiting no faults or distortions of the strata; but it is far from 
being less interesting either to the geologist or the general observer 
on that account. The rocks immediately underlying the superficial 
deposits consist of various members of the Silurian or oldest fossil- 
iferous strata. They belong to those divisions of the Silurian sys- 
tem called the Middle and Upper Silurian, corresponding to, and no 
doubt contemporaneous with, the Carradoc, Ludlow and Wenlock 
groups of England. Nowhere do we find a more interesting region 
in a geological point of view. Referring to it, or rather to the con- 
tinuation of the same formations in New York State, Sir Charles 
Lyell remarks :—‘ If we wish to see in perfection the oldest monu- 
ments of the earth’s history, so far at least as relates to its earliest 
inhabitants, we must look here. Certainly in no other country are 
these ancient strata developed on a grander scale, or more plentifully 
charged with fossils; and as they are nearly horizontal, the order of 
their relative position is always clear and unequivocal. They exhibit, 
moreover, in their range from the Hudson River to the Niagara, 
some fine examples of the gradual manner in which certain sets of 
strata thin out when traced to great distances, while others become 
intercalated in the series. Thus, for example, some of the lime- 
stones which are several hundred feet thick in the Helderberg Hills, 
near Albany, are scarcely forty feet thick in the Niagara district ;, 
and, on the other hand, the rocks over which the cataract of Niagara 
is precipitated, dwindle away to such insignificant dimensions when, 
followed eastward to the hills south-west of Albany that their place 
in the series can scarcely be recognized.”” Sir Charles adds ‘“ that 
a comparison of the fossil remains found in those ancient strata with 
those of a corresponding age and position on the other side of the 
Atlantic, shows that while some of the species are identical the. 
majority are not, and that however close the general analogy of the. 
forms may be, there is evidence of the same law of varieties in space, 
Vou. V. 2Nn 
