324 KANSAS CITY REVIEW OF SCIENCE. 
and they were aiso to be found throughout nearly the whole of the carboniferous 
sub-formations, as well as being associated with Permian strata in that country. 
Volcanic rocks also existed in the Devonian strata of Devonshire, but he knew 
of none in America or on the Continent, and the only instance of a volcano of 
Eocene age known to him was that near Verona. There were, however, well pre- 
served relics of Miocene volcanoes over many parts of Europe, and the evidence 
was clear that in nearly all geological ages they had played an important part,now 
in one region and now in another; and so far as his knowledge extended, at no 
period of geological history was there any sign of their having played a more im- 
portant part than they did in the present epoch. The mountain chains of the 
world were of different geological ages, some of them being of great antiquity, 
and some of them comparatively modern. It was well known that in North 
America the Lower Silurian rocks lay unconformably upon the Laurentian strata, 
and the disturbances which had taken place implied beyond a doubt that the 
Laurentian rocks formed a high mountain chain of pre-Silurian date, which had 
since constantly been worn away and degraded by sub-erial denudation. It 
would not be difficult to add other cases of recurrences of the upheaval and 
origin of special mountain chains, some of which he could speak of from per- 
sonal knowledge; but enough had been said to show the bearing of this question 
on the argument he had in view, namely, that of repetition of the same kind of 
events throughout all known geological time. The recurrence of rock and other 
salts strengthened his view. To give anything like a detailed account of all the 
fresh-water formations deposited in estuaries and lakes from the close of the Old 
Red Sandstone times down to late Tertiary epochs would be impossible in 
that address, but it might safely be inferred that something far more than 
the rudiments of our present continents existed long before Miocene times, 
and this accounted for the large areas of those continents, which were fre- 
quently occupied by Miocene fresh-water strata. With the main formations of 
Miocene age he was not now concerned, nor was it essential to his argument to 
deal with those Jater Tertiary phenomena, which in their upper stages so easily 
merged into the existing state of the world. The last special subject for discus- 
sion’was the recurrence of glacial epochs, a subject still considered to be heretical 
by many, and which was generally looked upon as an absurd crotchet when in 
1855 he first described to the Geological Society boulder beds containing ice- 
scratched stones and erratic blocks in the Permian strata of England. The same 
dea he afterward applied to some of the old red sandstone conglomerates, and 
of late years it had become so familiar, that the effect of glaciers had at length 
been noted by geologists from older paleozoic epochs down to the present day. 
The conclusions he arrived at were these. In opening his address he began 
with the subject of the oldest metaphoric rocks that he had seen, the Laurentian 
strata, the deposition of which took place far from the beginning of recognized 
eeological time, for there must have been older rocks by the degradation of 
which they were formed. Starting with the Laurentian rocks, he had shown 
