igoj. Cole. — A Geological Renaissance. iic^ 



feature is the exposure of granite through the drift along tlie 

 lines of railway near Dundrum and Kingstown. No one who 

 has ever used this map will wish to revert to the older and 

 somewhat conjectural " solid " one. When so much is con- 

 vej^ed b)^ the correct representation of deposits that were once 

 scorned as "superficial," it becomes quCvStionable if "solid" 

 maps should be published at all, except on a reduced scale for 

 the purpose of illustrating general structure. All available 

 dips appear, of course, on the drift map, which thus becomes 

 the one sound work of reference for geological and economic 

 enquiries alike. 



The complete mapping of the drift in Ireland cannot, how- 

 ever, be contemplated by the Survey, unless its forces are 

 largely increased. The number of workers allotted to Ireland 

 is probably as large as is at present reasonable in view of the 

 demands of Kngland, where several districts are being resur- 

 veyed, and of Scotland, where large areas of difficult structure 

 have yet to be examined. The present plan, we understand, 

 for Ireland is to issue drift maps of the countr}^ round im- 

 portant towns. Belfast has already been surveyed for this 

 purpose, and Cork follows in the present seavSon. These maps 

 will serve as useful types of what might be done with a larger 

 scientific staff. Meanwhile, a number of problems of geo- 

 logical structure, of modern palaeontology, and of petrography, 

 must perforce be laid aside in Ireland. 



Yet the new Memoir on the Dublin area shows how much 

 light may be thrown on debatable questions throughout the 

 country by a searching study of one particular district. So 

 far, the work is encouraging in the highest degree ; and the 

 association of the whole staff, by means of initialed para- 

 graphs, in the production of the Memoir, promotes a sense of 

 responsibility, and cannot fail to stimulate observation. This 

 practice has prevailed in previous publications ; but the Dis- 

 trict-Geologist has gone far in the present instance to en- 

 courage individual research, and has even admitted certain 

 revolutionary speculations (pp. 7 and 8), on the principle that 

 free discussion is the surest path to truth. 



Mr. M'Henry's suggestion that the Howth and Bray series 

 is younger than the shales that flank the L,einster granite, and 

 that the whole constitutes one sequence of Upper Silurian age, 



