No. 402.] EVENTS IN GEOLOGIC RECORDS. 499 
unusual event has been recognized. The action of the heavy 
storm is the truth sought but not brought out. 
It is fortunate that as the result of an unusual occurrence 
witnessed by Dr. Joseph Le Conte a rational explanation can 
be made of the conditions under which insects may be col- 
lected in vast numbers within the confines of a single stratum. 
As ordinarily interpreted, the contents of such a bed would indi- 
cate that this particular form of life existed in greater abun- 
dance at the time of its deposition than either before or after ; 
whereas, as shown by Dr. Le Conte, the abundance of insect 
remains may be due to concentration —a perfectly natural 
result though brought about by unusual conditions. He says: 
*On Lake Superior, at Eagle Harbor, in the summer of 
1844, we saw the white sands of the beach blackened with the 
bodies of insects of many species, but mostly beetles, cast 
ashore. As many species were here collected in a few days, 
by Dr. J. L. Le Conte, as could have been collected in as many 
months in any other place. The insects seem to have flown 
over the surface of the lake; to have been beaten down by 
winds and drowned, and then slowly carried. shoreward and 
accumulated in this harbor, and finally cast ashore by winds 
and waves. A small river emptying into the harbor carried 
also many beetles and ants. Doubtless,” he continues, “at 
Oeningen, in Miocene times, there was an extensive lake sur- 
rounded by dense forests, through. which ran a small river 
emptying into the lake ; and the insects drowned in its waters, 
and the leaves strewed by the winds on its surface, were cast 
ashore by its waves." 1 
Again, at the mouth of the Mackenzie River a vast quantity 
of driftwood is accumulating at the present time, which Sir 
Charles Lyell long ago predicted would, at some distant period, 
form a great deposit of coal. Now this accumulation of vege- 
table matter is that having its origin in a much warmer and 
well-wooded region. By the flooding of a great stream it is 
conveyed to its final resting place, which is a locality both 
climatically and biologically different —a region of low temper- 
ature and scant vegetation. Let us suppose that the buried 
1 Elements of Geology, Fourth Edition, p. 534. 
