Supercretaceous formations. 515 



SUPERCRETACEOUS FORMATIONS. 



In illustration of the history of the Eocene division of the tertiary 

 strata, Mr. Bowerbank has concluded, from his personal observations 

 at White cliff bay in the Isle of Wight, that there are no well-defined 

 zoological distinctions between the London and plastic clays, but that 

 in the cliffs of this bay the same shells are common to alternations 

 of these clays with one another. At Alum bay also he found many 

 London clay fossils in beds of greenish grey sand and clay below 

 the variegated sands and clays referred by Mr. Webster to the pla- 

 stic clay. A similar rectification was sometime ago proposed by 

 Professor Sedgwick. 



We have also witnessed during the past year the commencement 

 of a valuable publication by Mr. Bowerbank on the fossil fruits and 

 seeds of the London clay, illustrated with very numerous and accu- 

 rate engravings by Mr. James Sowerby. 



The great attention the author has long paid to the remains of fruits 

 and seeds which occur in such vast abundance in the Isle of Sheppy, 

 whence he has collected not less than 25,000 specimens, place him 

 in a position peculiarly advantageous for the object before him. 

 In this work drawings will be given of the anatomical structure of 

 many of these fossils, as seen under the microscope. The simple ex- 

 pedient Mr. Bowerbank has adopted of preserving these fruits in jars 

 of water, has kept him in the entire possession of every specimen 

 ever placed in his collection ; whilst of the thousands of similar 

 fossils that have been deposited in other collections, including that 

 at the British Museum, nearly all have perished from the decompo- 

 sition of the iron pyrites with which they are always penetrated. 



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 



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