174 Revieivs — Records of London Wells. 



1889, pp. 560-3). One other paper only do we miss from the 

 Bibliography, and that is by D. Mackintosh, entitled " Railway 

 Geology, No. 1, from Exeter to Newton-Bushell and Moreton- 

 hampstead" (Gkol. Mag., 1867, p. 390). He gave some account 

 of the small 'rock-basins' of Dartmoor, as also did Ormerod in his 

 paper of 1859, noted in the Bibliography. Their observations might 

 have been mentioned in the text. 



There is an interesting chapter on " Tertiary and Drift ", in which 

 is discussed the origin of the present physical features. These 

 include the plateaus (or relics of them) at elevations of about 800 and 

 1,000 feet; and the ravines, such as that of Lydford. Attention 

 is drawn to the ancient stream-tin deposits, and to the agents that 

 may have been at work during the Glacial period, leading to snow- 

 slope screes, etc. It is observed (p. 62) that "taken as a whole 

 the Dartmoor peat is rapidly wasting away", but locally there are 

 indications of active growth, and it would appear tliat in the tracts 

 above 1,600 feet the conditions of mist and cloud would be favourable 

 as noted (p. 1). Purther, it is remarked that "The peat-mosses, 

 just now of little economic importance, will be worked again as 

 fuel becomes more expensive and the better methods now in use 

 are applied ". At the same time, when the question of water-supply 

 is considered (p. 89), the value of the covering of peat in storing 

 water is pointed out, and it is questioned " whether it is advisable 

 to allow the peat to be removed, unless at the same time Dartmoor 

 is planted with trees ". Among the metalliferous deposits are ores 

 of tin, copper, arsenic, lead, silver, manganese, zinc, and iron, but 

 thei-e are few mines in work at the present time. "Tin, or perhaps 

 mixed tin and copper-ore, was probably worked in Devon and 

 Cornwall as far back as the bronze age," and " The manufacture 

 of pewter in the third century probably led to alluvial working for 

 stream-tin on Dartmoor". Particulars and sections of various mines 

 are given. Ochre and umber are obtained from open works at 

 Ashburton. 



From the foregoing remarks it will be evident how much there is 

 of scientific and practical interest in this well-written and carefully 

 edited memoir. 



Geological Survey Memoir. 

 IV. — Records of London "Wells. By G. Baeeow and L. J. Wills. 

 8vo ; pp. iv. 213, with 3 plates and 4 text-illustrations. Printed 

 for His Majesty's Stationery Office, 1913. Price 4s. 6d. 

 rilHIS work is a highly important supplement to the information 

 _L gathered during many years, chiefly by Mr. Whitaker, and 

 printed in Geological Survey Memoirs and other publications. The 

 general lowering of the water-level in the Chalk, on which the 

 supplies from the London wells and borings almost wholly depend, 

 was discussed so long ago as 1851 by Prestwich, and has been more 

 or less a matter of concern ever since. As remarked by the Director 

 in his Preface, recent observations show that "Not only is the fall 

 greater than was anticipated, but it has been taking place at an 

 increasing rate during the last ten years ". The need, therefore, of 



