1XV1 PROCEEDINGS OF THE GEOLOGICAL SOCIETY". ^May l( )°4> 



The death of William Talbot Aveline severs one of the few 

 remaining links connecting this generation with the heroic age 

 of English geology. Born in 1822. he joined the staff of the 

 Geological Survej' under De la Beche in 1840, when he was only 

 eighteen years old. At first he was stationed for a short period in 

 Somerset, on the Mendip Hills, but soon afterwards was transferred 

 to South Wales, the survey of which had now been begun. At 

 Fishguard he had as one of his associates Andrew C. Ramsay, who 

 had been appointed to the staff a year after him. In those days 

 such detailed mapping as is now required had not been dreamt of. 

 De la Beche, having made a masterly set of maps of the region 

 south of the Bristol Channel, was anxious that the country on the 

 north side of that estuary should be surveyed in the same broad, 

 generalized, and rapid manner. Nor in the state of knowledge of 

 the rocks at that time would any more detailed style of mapping 

 have been practicable. Nothing was known of the subdivisions of 

 the older Palaeozoic rocks there, and the condition of English 

 petrography did not admit of any detailed treatment of the igneous 

 masses. 



The surveyors were thus enabled to push on with comparative 

 rapidity across Southern and Central Wales. The older Palaeozoic 

 rocks were represented on the maps by one colour, and no attempt 

 was made to discriminate the varieties of the igneous rocks. But 

 in the course of years the necessity for greater detail came to be 

 strongly impressed on the minds of the more experienced members 

 of the staff, particularly Ramsay, Aveline, Jukes, and Selwyn. The 

 masterly researches of Sedgwick and McCoy had shown that what 

 had been taken for Lower Silurian strata belonged really to the 

 upper division of the system. Ramsay, realizing the great strati- 

 graphical importance of the striking break between the two series 

 at Builth, had joined with Aveline in reading before this Society, 

 in 1848, a ' Sketch of the Structure of Parts of Xorth & South 

 Wales,' in which the nature and significance of this great uncon- 

 formity and overlap were clearly stated. Aveline subsequently traced 

 in Xorth Wales the persistent group of the Tarannon Shales, and 

 showed how distinct is the horizon that they occupy. The necessity 

 for some revision of the early published maps was recognized by 

 Ramsay, long before he could obtain the consent of De la Beche to 

 undertake it. At length, as the last official act of his life, the 

 illustrious Director-General, then near his death, agreed that the 

 revision should be carried out. Aveline and J. W. Salter had been 



