358 Notices of Memoirs — The Geological Survey. 



z^OTiciES OIF" 3yE:EIs^OI:E^S- 



The Geological Survey of Great Britain and Ireland. 



Summary of Progress of the Geological Survey for 1897. 

 By Sir A. Geikie, D.Sc, D.C.L., LL.D., F.E.S., F.G.S., Director- 

 General. 8vo ; pp. 176. (London : Eyre & Spottiswoode, 1898. 

 Price Is.) 



{Continued from the July Number, p. 318.) 



2. Preparation op Maps, Sections, and Memoirs. — The results 

 obtained by the Geological Survey are made public in three forms : 

 ]Maps, Sections, Memoirs and Annual Reports, to which may be 

 added the arrangement of specimens in the three national museums, 

 with their diagrams, handbooks, and other explanatory matter, and 

 also the original papers, which, lying often beyond the scope of the 

 Survey's publications, are prepared by members of the staff and, with 

 the consent of the Director-General, are communicated by them to 

 scientific societies and journals. 



(a) 3Iaps. — Experiments were tried some years ago as to the 

 feasibility of producing the one-inch Geological Survey maps by 

 colour-printing. But the scale of these maps is so large, the number 

 of sheets so great, and the sale of many of them so comparatively 

 small, that this method of reproduction has not yet been adopted. 

 A large impression of each sheet would require to l3e printed off and 

 a considerable stock would accumulate, so that any additions and 

 alterations of the maps would be impracticable for many years. The 

 original system of colouring by hand, which has up to the present 

 time been retained, has this advantage, that by keeping the supply of 

 copies of each sheet just sufficient to meet the demands of the public, 

 any alteration of a map which from time to time may be found to be 

 necessary, can be made without the loss involved in cancelling a 

 large stock of copies. 



Colour-printing may eventually be applied to the new series of 

 one-inch maps. In the meantime it has been successfully tried in 

 the case of a general map of England and Wales on the scale of four 

 miles to an inch, to which reference will be made further on. 



Some idea may be formed of the nature of the colouring work of 

 the Survey maps, from the fact that upwards of 180 different tints and 

 combinations are employed to denote the various kinds of rocks 

 separatel}' discriminated on them. It is difficult to find colours distinct 

 from each other, yet harmonious, and that will not fade on exposure. 

 To guard as far as possible against the risk of fading, every colour is 

 also distinguished by its own symbol, which is legibly engraved 

 where the colour occurs on the map. 



Two editions of the one-inch map of England and Wales are 

 issued for those districts of which the Drift survey has been 

 completed, but where the drift covers small areas one edition is 



