84 SURVEY UNDER OFFICE OF WORKS CHAP, in 



of the Survey, and also in the career of its Local 

 Director, during the year 1846 was the appearance of 

 the first volume of the Survey Memoirs already re- 

 ferred to. Allusion to the coming volume was not 

 infrequent during the summer in the correspondence 

 of the Survey officials. Thus Sir Henry, who had 

 gone over to Ireland to inspect the field-work there 

 under the new Director, T. Oldham, 1 wrote : 



NEWTOWN BRAY, Co. WEXFORD, 

 2.6th July 1846. 



MY DEAR RAMSAY Oldham and self continue to get on 

 famously, and I am right well contented with him. . . . Oldham 

 appears to have a philosophical mind, quite ready to go ahead 

 in the school we have been forming. In about ten or twelve days 

 I hope to be on the start for the other (your) side of the Irish Sea, 

 running up to London to see what progress we are making towards 

 a house. 



Our tome of Memoirs is described as a handsome one; I 

 believe it to be a good one. The Longmans say it is too cheap, 

 but somehow 1 : is. seems a fair price for any work of the kind. 

 Ever yours, H. T. DE LA BECHE. 



We are here concerned with only Ramsay's con- 

 tribution to the volume. His essay on the Denuda- 

 tion of South Wales was a remarkably original and 

 suggestive addition to the literature of geology. It 

 was the first attempt to reduce the phenomena of 

 denudation to actual measurement by constructing 

 horizontal sections on a true scale, and showing what 

 thickness of rock had actually been stripped off the 

 face of the country. 



The following correspondence will show how this 

 essay was regarded by two of the ablest reasoners in 

 geological science : 



1 Thomas Oldham, born 1816, died 1878 ; appointed to the directorship 

 of the Geological Survey of Ireland in 1846 on the retirement of Captain James, 

 and held it until 1850, when he became Superintendent of the Geological Survey 

 of India. He retired from that office in 1876. 



