PRECAMBRIAN STRATIGRAPHY 
59 
As Dr. G. Steinman judiciously observes 7 the discovery of a 
great fauna in the Steep Rock Lake strata is not likely to ac- 
quaint us with forms so very different from those occurring in 
the typical Cambric rocks. This also was the opinion of Dr. 
Th. Tschernychew 8 who at the same time visited the same lo- 
calities. Both of these conclusions coincide with the circum- 
stances predicted by Prof. W. K. Brooks 9 more than twenty 
years ago — before any Pre-Cambrian fossils were known. 
Brooks’ reasoning was based strictly upon morphological 
grounds, and on this account has special value. His chief 
thought was that for some time prior to Olenellus times life 
which was entirely thalassic in nature was just beginning to 
find the bottom of the sea and was acquiring hard parts in 
order better to withstand its new shore environment. Hence 
for long periods previously life changed very slowly; but upon 
reaching shallow waters and the shore it differentiated with 
great rapidity. It is with these considerations in mind that 
the faunal aspects of the Pre-Cambrian rocks should be ap- 
proached, rather than with any expectation that it is going 
to be possible to classify the strata according to the same prin- 
ciples that are so universally followed in the case of the later 
geologic formations. 
At the close of the discussions on Pre-Cambrian problems 
at the Toronto Congress the bewildering variety of suggestions 
offered in correlation left the impression with the majority of 
delegates that the subject was in a state of hopeless confusion 
More mature reflection showed that this was not really the 
case. Identical problems were being met in distant parts of the 
world. Singularly, also, very similar sections had been made 
out on the different continents. The one feature that loomed 
largely in the minds of all was the fact that beneath the Olenel- 
lus level there existed everywhere a vast pile of sediments await- 
ing taxonomic grouping and systematic adjustment. It was 
not 'more intensive local cultivation that was most desired but 
some classifieatory scheme after the plan of that which we have 
for the later geologic formations. With such a framework upon 
which to hang all the accumulated facts and fancies negative 
testimony is as valuable as positive evidence, and the successive 
7 Oral communication. 
8 Oral communication. 
9 Journal of Geology, Vol. II, p. 455, 1904. 
