﻿February 28iJi, 1905.] PROCEEDINGS. xxix 



the Royal Society in 1891 by the Royal Medal. When he began 

 his work in 1870, the classification of the older Welsh rocks was 

 a battleground between two rival schools, and the Scotch High- 

 lands, North and South, presented a problem which defied the 

 efforts of the Scotch Geological Survey, and of the best amateur 

 geologists of the day. In defining the Ordovician Period he ended 

 the controversy between the followers of Sedgwick and those of 

 Murchisson, and set at rest for ever the vexed question of the 

 boundary of the Cambrian and Silurian systems. In dealing 

 with the Southern Highlands, he first of all discovered and 

 pointed out the invariable sequence of various forms of Grapto- 

 lites in the Silurian strata, and established their definite zones. 

 Then he used these zones to work out, with unwearied labour, 

 the complex faults and foldings, thus laying the foundation for 

 the subsequent maps and memoirs of the Geological Survey on 

 this most difficult region. Since that time his classification by 

 zones of Graptolites has been found to apply to the whole of the 

 Silurian rocks of the British Isles, and to all the foreign regions 

 in which it has been tested. 



His work in the Northern Highlands is of the same high 

 order. In 1882 he began work in the districts of Durness and 

 Eriboll, by marking down certain zones of rock by physical 

 character ( — for there were no fossils to guide him — ) and 

 gradually established the true sequence of the strata, and the 

 wonderful overthrust faulting and smashing of the rocks. Here 

 again he proved a guide to the Geological Survey, whose 

 memoirs and maps show that the Highlands have a structure 

 analogous, but, if possible, more complicated than that of the 

 Alps. 



In 1886 he turned his attention to the Shelve district or 

 Shropshire, and after two years work discovered the true base of 

 the Cambrian rocks characterised by Olenellus and its accom- 

 panying fauna, at the top of the basal Shropshire Quartzite. 

 This was followed later by the discovery of the Olenellus zone- 

 at Nuneaton, and led directly to the finding of Olenellus in the 

 Fucoid Reds of the Highlands. Thus a definite Lower Cam- 



