Notices of Memoirs — The Geological Survey. 311 



importance in relation to soils bad long been recognized, but their 

 great geological interest as records of the Glacial Period was more 

 gradually perceived. As the possession of a detailed topographical 

 map now enabled the surveyors to trace the superficial accumula- 

 tions with a precision quite unattainable on the old one-inch sheets, 

 it was determined to delineate the distribution of these surface- 

 deposits at the same time that the boundaries of the underlying 

 rocks were being followed. Hence in the six northern counties 

 of England, Scotland, and thenceforth everywhere in Ireland, the 

 drifts were distinguished and expressed upon the six-inch maps. 



The great practical and scientific advantages of carefully mapping 

 the superficial deposits on a large scale- were amply shown by the 

 esperienoe of a few years. It was found, however, that the tracing 

 of the distribution of the various kinds of Drift greatly increased 

 the amount of labour entailed in the preparation of the general map 

 of the country, thus necessarily diminishing the area surveyed 

 leach year and reducing the rate of progress of the Survey. At 

 last, in 1867, a great increase was made in the strength of the staff, 

 which was also reorganised with a view to greater efficiency. 

 A distinct branch of the service was established for Scotland under 

 a separate Director (A. Geikie), the English branch remaining 

 lender the supervision of A. C. Ramsay, and the Irish under J. B. 

 •Jukes, while Sir R. I. Murchison, who had succeeded De la Beche 

 an 18-&S, continued Director-General of the whole. 



At this important epoch in the history of its organization, the 

 Survey of England and Wales had completed and published the 

 maps of the country as far north as a line drawn from Liverpool 

 to Selby, and as far east as Retford, Melton Mowbray, Market 

 Harborough, Huntingdon, London, Chatham, and Folkestone. Con- 

 siderable progress had been made with the mapping of the north 

 of Lancashire and Westmoreland, and a portion of the great 

 Northumberland Coalfield had been surveyed. In Ireland the 

 maps of the larger half of the island had been published, and 

 the field-work had been pushed northwards to a line drawn from 

 ■Castlebar to Drogheda. In Scotland, where the staff had always 

 fceen disproportionately small, the maps of the basin of the Forth 

 Iiad been completed from the north of Fife to Berwick-on-Tweed. 

 The backward state of the Ordnance Survey had necessitated the 

 transference of the staff to the west side of the country, where 

 gix-inch maps were available, and some progress had been made 

 with the examination of the south of Ayrshire. 



The whole energy of the staff was now directed to the completion, 

 as quickly as possible, of the one-inch map of each of the three 

 kingdoms. That of England and Wales was finished in 1883, and 

 that of Ireland in 1887. The completion of these maps liberated 

 some of the officers in England and in Ireland, who were accordingly 

 transferred to the Scottish staff. As the Survey of Scotland was 

 commenced long after that of the sister kingdoms, and was carried 

 on for many years by a staff of only two surveyors, it is not yefc 

 comjDleted. At the present time the uusurveyed portions of the 



