4 
GRAND DISCOVERIES OF LIFE 
parable not to the Cambric, or Siluric, section alone but to an 
equivalent, perhaps, of the entire Paleozoic column. Moreover, a 
third such sequence below all the others was foreshadowed before 
the truly Azoics were to be regarded as reached. On the north 
shore of Lake Superior life remains were disclosed low down in 
the older of the new systems, at a time-level twice as remote as 
that which elapsed between the deposition of the basal Cambric 
beds and the sedimentaries of our day. So the biotic effects of 
the discovery of the bottom of the sea still held good despite the 
fact of the removal of the immediate field of its testing. 
When Darwin composed his Origin of Species no sedimental 
section older than that of Cambric age was known. He astutely 
observed that if his theory be true “It is indisputable that before 
the earliest Cambric stratum was deposited long periods elapsed, 
as long as, or probably far longer than the whole interval from the 
Cambric age to the present day; and that during these vast periods 
the world swarmed with living creatures.” Although he could 
give no satisfactory reason at the time to the question why no 
fossiliferous deposits of this early period had been found, and 
notwithstanding the fact that he realized in this circumstance the 
gravest objection that could be urged against his hypothesis, re¬ 
cent discoveries in America carried the life record backward far 
beyond his most sanguine expectations. It was the bridging of 
this early gap that made the dissertation on life’s discovery of the 
bottom of the sea so novel, so pertinent and so fascinating. 
Brooks once emphasized the factors of the rapid intellectual 
development which has taken place among the mammals since 
Mid Tertiary times, and the abrupt changes which have trans- 
spired in both animals and plants when the land fauna and the 
flora were established, which were well known, but the circum¬ 
stance that the discovery of the bottom of the sea by life initiated 
a much earlier and probably more important era of rapid develop¬ 
ment in the forms of animal life was never before pointed out. 
Next to original creation of organic matter settlement of or¬ 
ganisms upon the floor of the ocean was probably the most 
momentous single event in the entire history of life on our 
planet. The simplicity, abundance, freedom from danger, and the 
lazy conditions which primitive pelagic life enjoyed quickly 
changed in those regions where crustal upheaval occurred and 
where the waters became relatively shallow, to complexity, scare- 
