Reviews — Hceviatite and Rutile. 427 



noted a few trifling misprints, especially in the tables, the book seems 

 to be remarkably free from errors, and gives evidence of a great 

 amount of careful work and investigation of the complicated and 

 scattered literature on the subject. 



HEMATITE AND RuTILE FORMED BY THE ACTION OF ChLORINE 



AT High Temperatures. By H. E. Merwin and J. C. 

 HosTETTER. The American Mineralogist, vol. iv. No. 10, 

 October, 1919, pp. 126 and 127. 



TRON and titanium compounds were removed from the walls 

 -*- of a glass - pot by the action of chlorine at temperatures 

 between 1000° and 1100° C, and deposits of haematite and rutile 

 crystals of comparatively large size were formed. The haematite 

 crystals were 4 mm. in diameter and the rutile crystals about 

 1 mm. long. The angles between the faces were measured and 

 found to agree with those of the natural minerals. Haematite was 

 shown to contain a very small proportion of FeO in solid solution, 

 and it is suggested that this method might be used to prepare 

 crystals with varying amounts of FeO in order to study possible 

 variations in the angles. 



W. H. W. 



The Economic Geology op the Central Coalfield of Scotland, 

 Area VII (Rutherglen, Hamilton, and Wishaw). Mem. 

 Geol. Survey, Scotland, pp. vii + 140, with 6 plates and 

 4 figures. 1920. Price 7s. &d. net. 



OEVERAL of the memoirs of this series have already been noticed 

 ^ in the Magazine, and this volume follows closely on the lines 

 of its predecessors. It deals with some of the most important mining 

 ground in the county of Lanark with a small area in Renfrew, 

 extending from Rutherglen to Newmains, including Cambuslang, 

 Uddingston and Bothwell, Hamilton, Motherwell, and Wishaw. 

 The district on the whole forms part of a deep basin, running from 

 north-west to south-east, with its centre near Uddingston, and limited 

 on the south-west by the Dechmont fault, with a throw of about 

 3,600 feet. Owing to the depth of the coals in the centre of the basin, 

 they formed a reserve for some time, while neighbouring districts 

 were approaching exhaustion, but even this has now been 

 extensively worked, and it is improbable that the output will increase 

 very much, though it may be maintained for a good many years. 

 In 1913 the county of Lanark yielded 41 per cent of the total Scottish 

 coal-production. 



The district is almost entirely composed of Coal-measures, with 

 a small strip of Millstone Grit in the north-east, and Lower 

 Carboniferous rocks only to the south-west of the great Dechmont 

 fault. There are also various superficial deposits, including 

 pre-Glacial sands and gravels, boulder-clay, and various sands, 



