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 I 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 beds, and containing boulders of 

 granite, trap and other rocks. 



This clay is known on the east and 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 



