Reviews — Dr. W. Gibson — Geology of Coal and Coal-mining. 323 



The author, from his personal experience, speaks guardedly about 

 the testimony of the fossils : thus plants " are of service to the miner, 

 only in a broad, general sense," whereas moUusca " in many coalfields 

 fix the horizon of a particular bed." Much yet remains to be done, 

 as we have yet to learn to what extent the vertical distribution of 

 fossils in the Midland coal-basin holds good for other British coalfields. 

 The fact, however, of their local importance should stimulate the 

 interest of mine-managers, and induce them to collect and carefully 

 record the horizons of fossils. The illustrations given of fossil plants 

 are so excellent that they may well stir up enthusiasm. 



"While knowledge is required in the extension of workings beyond 

 the limits of a coalfield, so also is it wanted in unknown areas. Coal- 

 seams are very rarely exposed in cliffs and other natural sections, and 

 even in trial borings they may be missed, because it is difficult with 

 present contrivances to bring up good cores of coal, as it may be ground 

 to powder. 



An acquaintance with the characters of coal-bearing strata here 

 comes to the help of the prospector, to whom the author gives much 

 useful and judicious advice. Here also the occurrence of certain 

 fossils may prove of ready assistance in negativing the prospect of coal 

 or in encouraging enterprise. 



The author gives brief accounts of the British coalfields and of 

 those in various parts of the world. If he devotes more space to the 

 Somerset and Gloucester coalfield than to that of South Staffordshire, 

 it may be because in the latter the available quantity of coal that 

 remains is estimated to be little more than one-third of that remaining 

 in the Somerset and Gloucester area. The Yorkshire, Derbyshire, and 

 Nottinghamshire coalfield " contains the largest reserve of coal in the 

 British Isles" — presumably., we should add, for there are still large 

 unproved areas in the south and east of England. 



There is an ambiguity (on p. 44) where the author speaks of the 

 chief coal-seams in the Southern Hemisphere and in India as belonging 

 either to the Mesozoic or Tertiary period, because (on p. 46) he places 

 the coalfields of South Africa, India, and Australia in the Palaeozoic 

 (Permian and Permo-Carboniferous). 



We have left no space to refer to the many other matters of interest 

 dealt with in this volume, such as the characters of coals and coal-seams, 

 their origin and extent, the depth of mines, the faults and folds, and 

 general structure of coalfields, illustrated by diagrams, but we may 

 note that the map on p. 117 requires a further explanatory legend. 



In all these matters above-mentioned, the author gives sound 

 practical information, in which the doubts and difficulties and 

 exceptions are very freely stated. In fact, one might conclude that 

 with the increasing knowledge and importance of the subject a 

 geological coal-mining expert must be a necessary officer in every 

 coalfield. 



