166 NOTICES OF THE MEETINGS [April 2, 
Sir C. Lyell then exhibited some sections, recently published by 
Mr. Prestwich,* illustrative of the geology of the environs of London, 
and gave a rapid sketch of the successive Eocene groups from the 
London Clay and overlying Bagshot series with its nummulites to 
the Barton and Hampshire freshwater formations with their fossil 
quadrupeds. He then alluded to the tertiary strata next in the 
ascending order which he had recently studied in Limburg, Belgium, 
which are not represented in England, and next to the Miocene 
faluns of Touraine and the Pliocene strata or crag of Suffolk, and 
lastly to the still more modern glacial period and the brick-earth 
of the valley of the Thames. The last mentioned formation contains 
the bones of extinct quadrupeds mingled with shells of recent species 
terrestrial and fluviatile. 
The numerous and important changes in the fauna of the globe, at- 
tested by these successive assemblages of extinct species, belonging 
to different tertiary eras, attest the vast lapse of ages, which separate 
the time when the freshwater beds of Woolwich and Blackheath were 
formed from the human period. But revolutions of another and no 
less striking kind have taken place contemporaneously in the physi- 
cal geography of the northern hemisphere, revolutions on so great a 
scale that the greater part of the present continents of Europe, Asia, 
Northern Africa and North America with which the geologist is 
best acquainted, have come into existence in the interval of time 
here alluded to. It may also be confidently affirmed that the colos- 
sal chain of the Alps is more modern than the tertiary shingle of 
Blackheath. There was deep sea at the period when the London 
Clay was forming, precisely in the area where the loftiest mountains 
of Europe now rise into the regions of perpetual snow. In proof 
of this the Lecturer referred to the works of several modern geolo- 
gists, especially to those of Sir Roderick Murchison, and to a Lecture 
delivered by Sir Roderick in the Royal Institution to show that the 
nummulitic formation which belongs to the Eocene period, and not to 
the very oldest part of that period, attains an elevation in some por- 
tions of the Swiss Alps of 8,000 or even 10,000 feet, and enters 
into the structure and composition even of the central axis of the 
Alps having been subject to the same movements and partaking of 
the same foldings and contortions as the underlying cretaceous and 
oolitic strata. 
Sir Charles Lyell next proceeded to show that a great series of 
volcanic eruptions had occurred in Europe since the older Eocene 
strata of the neighbourhood of London were deposited. Not only 
Vesuvius and Somma as well as Etna and the extinct volcanoes of 
Southern Sicily but the trachytic and basaltic eruptions of the ex- 
tinct volcanoes of central France are more modern than the London 
Clay. The evidence consists not only of the superposition of igneous 
rocks several thousand feet thick, to lacustrine strata of the middle 
* « Prestwich, Geological Enquiry respecting the ‘Water-bearing strata 
around London, &c.”’ Van Voorst, 1851. 
