lviii PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1 895, 



reference ; for, apart from its original information, it gave evidence, 

 as did all his writings, of a thorough study of the publications of 

 other observers, and a full acknowledgment of all that they had done. 



Meanwhile Topley had been instructed to proceed to the Coal- 

 field of Northumberland and Durham, and much of his literary 

 labour connected with the memoir had to be performed in that 

 northern region in the winter-time, or at other seasons when field- 

 work was impracticable. In 1868, after six years' service, he had 

 been advanced to the rank of Geologist on the Geological Survey. 



"When, in 1872, the Committee of the Sub-Wealden Exploration 

 commenced their active operations near Battle, Topley was, of 

 course, specially interested. He was one of the first to be consulted, 

 and, later on, he was expressly sent by the Geological Survey to the 

 locality to examine and report upon the cores brought up by the 

 boring-apparatus. He was thereby enabled to record, in his memoir 

 on the Geology of the Weald, particulars of the strata and their 

 fossils to a depth of over 1000 feet. The classification of the strata 

 given in that work was subsequently modified, and Topley from 

 time to time contributed many reports and other articles on the 

 subject. 



A considerable portion of Topley's sojourn in the north was spent 

 at Eothbury, near Morpeth, and at Alnwick, where his studies 

 were directed mainly to the Carboniferous rocks and to the Glacial 

 Drifts. The nature of that great sheet of basalt known as the 

 Whin Sill engaged his attention and that of his friend and former 

 colleague, Prof. Lebour, 1 and the result of their observations was to 

 prove its intrusive character. 



The subject of Denudation never ceased to interest Topley, and 

 when, during the early sixties, many warm discussions took place 

 concerning the origin of escarpments and other features, he joined 

 in the fray on behalf of subaerial agents. In confirmation of views 

 that had been expressed with regard to other regions, he pointed 

 out how in East Yorkshire anticlinals, by their fissured summits, 

 had been readily acted upon by inland agents of erosion, whereas, 

 in certain cases, synclinals had better withstood the assaults of rain 

 and rivers. 



In 1880 William Topley was called upon to abandon his field-work 

 in Northumberland in order to superintend the publication of Maps 

 and Memoirs at the Geological Survey Office in Jermyn Street. 



1 Brit. Assoc. Rep. Bradford, 1873 (Sections), p. 92 ; Quart. Journ. Geol. 

 Soc. vol. xxxiii. (1877) pp. 406-422. 



