lxvi PROCEEDINGS OP THE GEOLOGICAL SOCIETY. [May I9OO, 



of our knowledge, accompanied of course by greater precision in the 

 recording of facts. 



In this matter, perhaps, I shall not be accused of over-partiality 

 in saying that it is largely due to the extension of Geological 

 Surveys. There were but few when I joined our own ; now there 

 are many. One result of the continuous, more or less detailed, 

 mapping done by Government Surveys has been to make the value 

 of such work more widely known, and also to lead geologists, other 

 than those employed in the work, to take it up for their own local or 

 special purposes. It is more common now than it was in my early 

 days to find a geologist engaged in putting bis work on a map, and I 

 hail this chauge with great satisfaction. The more numerous are the 

 geologists who themselves make maps, the more will geological maps 

 be appreciated, and the more will an official Survey be expected to 

 produce maps giving a great amount of precise and detailed in- 

 formation, such as a Survey alone can do over large tracts. 



The advance in the mapping-work of the Geological Survey may 

 be noticed here, an advance depending largely on the publication of 

 newer, better, and more detailed maps by the Ordnance Survey. 



In my early days Drew started the divisions of the Hastings 

 Beds in the Wealden area, in Kent, Surrey, and Sussex, as well 

 as those of the Lower Greensand around its border. I wonder 

 what we should think if our maps showed us those two formations 

 in the lump in that large district, although we sometimes dispute 

 as to the correlation of their divisions in various districts. 



Now, in the new work, the Chalk also is separated into three, or 

 sometimes four divisions ; but this work, alas ! has not yet reached 

 Kent and Surrey. In like manner more detailed work has been 

 done in the Tertiary beds of Hampshire and Dorset, in the Jurassic 

 of the latter county, in the New Red and Devonian of Devon 

 and Cornwall, in the Carboniferous and Old Red Sandstone of South 

 Wales, and in various formations in the Midlands. 



But perhaps the greatest, as certainly it is the most widespread 

 of all improvements, is the gradual evolution of Drift-mapping. 

 This mapping started in a generalized way, with an apparently 

 contemptuous reference to a more or less troublesome and objection- 

 able mass of Drift, in the lump ; but the importance of these 

 surface-deposits has become more clearly seen, so that now they are 

 mapped according to their various lithological characters. In a few 

 cases, perhaps, divisions, according to presumed age or origin, may 

 be somewhat in excess ; but in this the Survey maps certainly lag 



