488 Geological Society. 
other portions of these plants have been drifted, to various distances, 
from the swamps, savannahs, and forests that gave them birth, par- 
ticularly those that are dispersed through the sandstones, or mixed 
with fishes in the shale beds. 
The cases are very few in which J have ever seen fossil trees, or 
any smaller vegetables erect and petrified in their native place. 
The Cycadites and stumps of large Coniferous trees on the surface 
of the oolite in Portland, and the stems of Equisetaceous plants 
described by Mr. Murchison in the inferior oolite formation near 
Whitby, and erect plants which I have found in sandy strata of the 
latter formation near Alencon, are examples of stems and roots over- 
laid by sediment and subsequently petrified without removal from 
the spots in which they grew. At Balgray, three miles north of 
Glasgow, I saw in the year 1824, as there still may be seen, an un- 
equivocal example of the stumps of several stems of large trees stand- 
ing close together in their native place in a quarry of sandstone of 
the coal formation. 
SUPERCRETACEOUS FORMATIONS. 
Mr. Lyell has communicated to us a paper full of elaborate detail 
of facts, and of ingenious speculations respecting the Boulder forma- 
tion, or drift, associated with freshwater deposits, in the mud 
cliffs of Eastern Norfolk. These cliffs are in some places 400 feet 
high, and consist of chalk, crag, freshwater deposits, drift mud and 
sand, stratified and unstratified ;—with superficial accumulations 
of flint gravel. The centre of his observations is the town of Cro- 
mer; he considers the Boulder formation to have been accumulated 
on land permanently submerged, and not, by one or many, transient 
advances of water over dry land, and therefore proposes, as Mr 
Murchison and others have already done, to substitute the term of 
Drift for that of Diluvium, which many other writers have assigned 
to it. The Drift, or Diluvium, is of two kinds; one composed of 
sand, loam, clay, and gravel, all regularly stratified ; the other con- 
sisting of clay, not divided into sated and containing boulders of 
granite, trap and other rocks. 
This clay is known on the east aie north-east coast of Scotland 
by the name of Till. He considers the stratified Drift and Till to 
be contemporaneous formations, and compares the latter to moraines 
formed at the termination of glaciers. He imagines that drifted 
masses of ice, charged with earthy matter and fragments of rock, 
may have deposited the Till as they melted in still water, and the 
occasional intercalation or juxta-position of stratified materials is 
ascribed to the action of currents on materials also falling from 
melting icebergs. 
Mr. Lyell refers the complicated bendings and tortuous foldings 
of many beds of this formation near Mundesley and Cromer to la- 
teral pressure from drifting ice, especially where extremely con- 
torted beds repose upon undisturbed and horizontal strata. But he 
admits that some of them may be due to landslips of ancient date, 
and which had no connection with the present line of cliffs. At 
