30 Revieivs — W. C. Lucy on the Gravels of the 8evern, etc. 



rests upon the Northern drift. But this latter gravel occurs at all 

 elevations, being found at the height of 750 feet on the Cotteswolds, 

 and also lying in terraces 15 to 50 feet above the river-levels. 



The Northern drift, which at Cropthorne was described by Mr. 

 Strickland, contains mammalian remains and numerous species of 

 mollusca — marine, land, and freshwater. 80 feet is the highest 

 point at which the mammalian remains have been found in the 

 gravel. In the clay bands of the Oolitic gravel, land and freshwater 

 shells occur. 



Mr. Lucy describes a great many sections in detail, carefully 

 recording their altitudes, and he gives lists of the organic remains 

 which have been found. Quartz pebbles have been discovered in clay 

 which fills fissures in Oolite quarries on the Cotteswolds, at an 

 elevation of about 750 feet. These are considered as a relic of the 

 Northern drift. Analyses of the clays are given, and the author 

 hints at their being Boulder-clay, though of course this is extremely 

 doubtful. 



There is, in addition to the other gravels, a small sub-angular 

 Oolitic gravel found in parts of the Cotteswold Range, at heights 

 varying from 500 to 700 feet, which is due to the denudation of the 

 Inferior Oolite. It contains no fossils nor recent shells, and seems 

 to attain a uniformity of character. It was this deposit that Mr. 

 Hull called raised sea-beaches in his Memoir on the geology of the 

 country around Cheltenham. Mr. Lucy is opposed to this opinion. He 

 attributes the gravel to frozen snow or land-ice, which when the 

 thaw set in would slip down, carrying with it the detritus of 

 the Inferior Oolite; and he regards it as formed, after the rigour 

 of the Glacial period, at an age when the climate had become com- 

 paratively mild. 



It is not uncommon in gravel pits to notice a marked majority of 

 the pebbles lying with their longer axes vertical. The origin of this 

 peculiar position of the pebbles has attracted the attention of several 

 geologists. The Eev. 0. Fisher, in his interesting paper on the 

 " Warp," remarks that this effect is probably not always produced 

 in the same way, and he suggests, as one of the possible causes of 

 the phenomenon, the fact that in a pebble sinking through mud the 

 friction would play a more important part than the resistance, 

 especially if its motion were slow ; and the effect of friction would 

 be to place the pebble on end. Mr. Boyd Dawkins notices similar 

 cases when " the long axes of the pebbles are in the main vertical, 

 instead of occupying the horizontal position of those which have 

 been deposited by water," and he refers to the deposit as beyond all 

 doubt of Glacial origin — to have been borne down by ice, and 

 deposited on its melting. Mr. Lucy draws attention to the remarks 

 of Mr. Dawkins when speaking of the phenomenon, but he explains 

 it as " showing lateral pressure." 



Coming to the denudation of the Cotteswold Hills, Mr. Lucy 

 maintains that the flat table-land of the Cotteswolds is mainly 

 attributable to the denuding power of forces that brought the 

 pebbles which occur there at the high level, most of which were 



