232 RevieiDS — The Geology of the Fenland. 



all the old records of the district and ejjitomized them ; a study 

 which is most important for the proper understanding of the present 

 state of the Fenland. Notices of the chief drainage works, descriptions 

 of the physical features, and accounts of floods and storms are given. 



The questions of evaporation and drainage are discussed in some 

 detail, and the author draws attention to and describes an instru- 

 ment designed by Mr. S. H. Miller, F.K.A.S., and himself, called 

 the Evaporimeter ; the object of which is to ascertain the effects of 

 different soils upon evaporation. 



Full accounts of other meteorological matters, such as rainfall, 

 winds, etc., are given. These and other details render the work as 

 much a manual of the Archeeology and Physical Geography of the 

 Fenland, as of its Geology. 



One chapter of especial interest to geologists is that on the Boulder- 

 clay. This deposit skirts the Fenland, and in Mr. Skertchly's opinion 

 underlies most of that area, and is in some places surprisingly thick. 



Thus the well sunk in 1828, at Boston, pierced beds to a depth 

 of 572 feet, the whole of which he states to be Quaternai-y ; and of 

 these the Boulder-clay is estimated to have a thickness of 460 feet. 

 The shells which are mentioned at various depths belong to the 

 genera Gryphcea and Ammonites, specimens of which have been 

 preserved. These, he states, are all glaciated. 



This is the Chalky Boulder-clay, and Mr. Skertchly argues that it 

 is of terrestrial origin. He points out, in support of this view, that 

 its included materials vary according to the nature of the deposit over 

 which it is spread. At the same time Chalk is almost invariably 

 present. If it were iceberg drift, the component materials must be 

 those of the distant gathering grounds, and not those of the rocks 

 they fall upon as the berg melts away. Moreover, for icebergs to 

 carry the debris, we must admit a submergence of at least 500 feet, 

 and granting this, then very little Chalk would be left above water, 

 and no traces at all of the Oxford and Kimmeridge Clays, the wrecks 

 of which are locally abundant in the Boulder-clay. 



There is an account of the great boulder of Cretaceous rocks at 

 Eoslyn Hole, Ely, which formerly led to much discussion in the 

 pages of this Magazine, and Mr. Skertchly states that he has seen 

 Boulder-clay underlying these transported beds. 



A classification of all the beds in the Fenland, with remarks on the 

 physical conditions which attended their deposit, is given, and the 

 author points out that he independently came to similar conclusions 

 concerning the Glacial and Post-Glacial events, to those arrived at 

 by Dr. James Geikie, and published in " The Great Ice Age." He 

 briefly adverts to his discovery of palseolithic implements in inter- 

 glacial brick-earth beneath the chalky Boulder-clay near Brandon, a 

 further account of which is promised in a Memoir on the Gunflint 

 Factory, Until all the details of such an interesting discovery are 

 made known, we must be content to suspend our judgment. Never- 

 theless, however startling it may seem, and however much opposed 

 to our early teachings and convictions, so much new light has been 

 thrown on the physical and palaeontological history of the Glacial 



