319 



GLACIATION OF THE SOUTH DOWNS.* 



The study of the Ice Age or Ages and of the Pleistocene Period as a whole 

 is always fascinating on account of its intimate and direct connexion 

 with the scenery as we know it, and with the history of man. Much 

 work has been done in recent years, and we are gradually approaching a 

 clearer conception of the physical history and vicissitudes of England 

 as far south as the Thames Valley, beyond which true glacial deposits 

 have not been recognised. \\Tiat was happening in the Wealden area 

 and on the south coast is a difficult question, and one well deserving the 

 attention of competent geologists. Unfortunately we cannot congratulate 

 Mr. E. A. Martin on his paper on ' Glaciation of the South Downs.' 



His ' first leanings towards the idea that the Downs were fashioned 

 in the outline that they now present by the aid of glaciers was caused 

 by a sense of the inability of any agency other than ice to give to the 

 Downs the rounded forms that they present ' ; he regards the Downs 

 as ' merely magnified roches moutonnees covered with turf,' although 

 he recognises that ' they have each one become rounded to such a form 

 as no other kind of rock would have assumed.' We would ask Mr. Martin 

 what agency could give to Chalk Hills any other form than that of 

 rounded downs. Clement Reid has suggested that under a cold climate 

 the chalk surface would be frozen, and therefore impervious, to account 

 for certain features in some of the chalk valleys, but Mr. Martin invokes 

 glaciers to explain what Reid and any geologist would regard as typical 

 chalk scenery produced under normal conditions. Having made his 

 fundamental assumption, Mr. Martin seeks to support it by a mass of 

 observations and references to authorities, but after reading his paper 

 several tinaes, we must confess to utter bewilderment ; indeed, v/e can 

 hardly believe that he has himself arrived at any consistent theory. 

 He makes much of the blocks, sarsen, conglomerate, etc., ' enormous 

 erratics ' easily accounted for if ' solid water be admitted as their means 

 of transport ' ; but while he regards them as transported by glaciers 

 which carved out the downland valleys, he also quotes Searles Wood, who 

 ' thought that during the formation of the Boulder Clay of Central Eng- 

 land, the Weald was covered by the sea. If so, is it to be supposed this 

 sea was not the home of ice -bergs and ice-floes ? ' Has Mr. Martin made 

 up his mind between the rival claims of a marine submergence and of an 

 ice-sheet with glaciers, or has the summer of 1921 so affected him that 

 anything cold will suffice ? 



Again, his scheme, if he has one, has not been adjusted to any chrono- 

 logical sequence ; sometimes he distinguishes the post-Mousterian cold 

 period, which produced the Coombe Rock, from an earlier glaciation at 

 the close of the Acheulian ( !) period, sometimes there is only one which 

 appears to follow closely on a Pliocene marine planation. It is only by 

 careful and patient work that a consistent account of the Weald and 

 the Downs during the Pleistocene period will be reached. As Mr. Martin 

 quotes George Borrow {sic) on the Pliocene of the Chilterns, we recom- 

 mend him to turn his attention to the ' Bible in Spain,' and leave geol- 

 ogical subjects to geologists. — ^C. N. B. 



A Book about Plants and Trees, by R. and S. G. Gurney. 



London : C. A. Pearson, Ltd., pp. xvi. and 103, 1/6 net. Boy Scouts 

 and Girl Guides are to be congratulated on having had prepared for their 

 use this simple book about plants, which serves as a text book for those 

 wishing to qualify for the Naturalists' Badge. The book is divided into 

 four parts, dealing respectively with the life and food of plants, an account 

 of five plants as examples of life histories, how to group plants in a 

 nature diary, and, lastly, a description of thirty different species of 

 trees. There are many helpful outline drawings, and the descriptions 

 are not only simply and pleasantly written, but much more reliable, and 

 the teaching is on sounder lines than usual in a popular treatise. 



* By Edward A. Martin, in Trans, S.E. Union of Sci. Soc, for 1920. 

 1921 Sept. 1 



