The Work of the Geologiccd Survey. 
143 
separate organisation, but its members may be interchanged. It 
consists of two grades : (a) district surveyors, geologists, and assis- 
tant geologists, whose chief duty, under the superintendence of 
their director, is the preparation of the maps, sections, and memoirs, 
and ( b ) collectors, who, under the supervision of the other officers, 
search for fossils and collect specimens of minerals and rocks for 
determination and for exhibition in the museums. There is an office 
and likewise a museum in London, Edinburgh, and Dublin. Each 
branch has thus its own headquarters, with a small resident staff, the 
head office for the whole Survey being the establishment at 28 Jermyn 
Street, London, S.W. The total strength of the service in the United 
Kingdom, including the officers engaged in museum work, is at pre- 
sent 60. As the duties are practically the same in each branch of 
the Survey, I shall treat the whole as one service and describe its 
work under the following heads : — 1st, mapping ; 2nd, petrogra- 
phical determination ; 3rd, palaeontological determination ; 4th, the 
collecting of rocks, minerals, and fossils ; 5th, the preparation of 
maps, sections, and memoirs for publication ; 6th, museum work ; 
7th, general administration ; 8th, relations of the service to other 
Government departments and to the general public, as regards the 
furnishing of geological information. 
I. Mapping. 
The first and most important duty of the Survey is to map in 
detail the geological structure of the country. When this task was 
first undertaken by De la Beche and his associates they employed 
the Ordnance Survey maps on the scale of 1 inch to a mile 
which had then been published for Cornwall and Devon. These 
early Ordnance sheets, however, were imperfect and incorrect in 
their topography, having been among the first undertakings of the 
Ordnance Survey, before methods of surveying had been brought to 
the perfection that has since been attained. The connexion 
between the Geological and the Ordnance Surveys was at first so 
intimate that the former was instituted as a subsidiary branch of the 
latter. The geologists belonged to the “ Ordnance Geological Sur- 
vey,” and though they were never under military orders, they wore 
a uniform. The only surviving relics of that connexion are some of 
the waistcoat buttons, which on festive occasions continued to be 
worn after the rest of the raiment had disappeared. But from the 
first, and up to the present day, the Ordnance maps have been the 
basis on which all the geological work has been conducted. We 
have heard much in the last few years of the inaccuracies and im- 
perfections of these maps. But the experience of the Geological 
Survey does not bear out this charge. I do not suppose that these 
maps have ever been put to a severer test than by the officers of the 
Geological' Survey, who have carried them into every nook and 
corner of the country, from coast- line to mountain-top, and have 
checked them in many ways while fixing the positions of geological 
lines. It is, of course, admitted that the old 1-inch maps are un- 
