488 A. Strahan — Geological Survey of South Wales, etc. 



I am not here concerned to prove the correctness of these 

 suggestions in every case. It is quite enough to draw the attention 

 of geologists to the necessity of looking out for and interpreting 

 these aggregates ; they will then determine, step by step, which 

 deposits ought rightly to be included in the category. 



II. — On the Eevision of South Wales and Monmouthshire by 

 THE Geological Survey.^ 



By A. Strahan, M.A., F.G-.S. 

 [Communicated by permission of the Director-General.] 



THE original geological survey of South Wales was made under 

 the direction of Sir Henry de la Beche. The exact date of its 

 commencement is uncertain, but I am informed by Mr. Aveline that 

 in 1840, when he joined, the staff was engaged in the neighbourhood 

 of Cardiff, and in 1841 Ramsay on his appointment found that the 

 survey had progressed westwards into Pembrokeshire, and was at 

 work at Tenby and St. David's.* By the end of 1845 the maps had 

 all been published. A complete list of the names which appear on 

 them consists of H. T. de la Beche, J. Phillips, D. H. Williams, 

 A. C. Earasay, W. T. Aveline, J. Eees, T. E. James, W. E. Logan, 

 H. W. Bristow, and H. B. Woodward.^ 



Previously, however, to the entry of the Survey into South 

 Wales, a considerable tract had been mapped by Sir W. E. Logan. 

 " Unaided he commenced, in 1831, a geological survey of part of 

 the great South Welsh Coalfield, extending from Crown (Cwm) 

 Avon to Carmarthen Bay, and completed it in seven j'ears, at no 

 small pecuniary sacrifice. Such was the estimate of the accuracy 

 and value of this survey by the late Director of the Geological 

 Survey of Great Britain, Sir Henry de la Beche, that with Sir 

 William's consent it was adopted as part of the national work."* 

 At the meeting of the British Association in Liverpool in 1837 

 Logan exhibited his work, and in 1842 it was referred to by 

 De la Beche as a beautifully executed map.^ After the lapse of 

 nearly fifty years these maps, admirable though they were con- 

 sidering their date and the circumstances under which they were 

 made, had become obsolete. Not only was the topography scarcely 

 recognizable, but the development of the steam-coal trade had led to 

 the opening out of many of the Monmouthshire and Glamorganshire 

 valleys and the working of what was practically a virgin coalfield. 

 On June 8, 1891, in the House of Commons, Lord Swansea (then Sir 

 Hussey Vivian) asked the Vice-President of the Council whether in 



^ Read before Section C (Geology), British Association, Bristol, September, 1898. 



^ "Memoir of Sir Andrew Crombie Ramsay," by Sir Archibald Geikie, 1895, 

 p. 42 ; London, 8to. 



3 Revisions chieflv of the Secondary Rocks in 1864, 1871, and 1872. 



* An article in The Times of July 24, 1862, by Dr. Percy, quoted in " Life of 

 Sir William E. Logan, Kt., LL.D., F.R.S., F.G.S.," by B. J". Harrington, 1883, 

 p. 349 ; London, 8vo. 



5 Ibid., p. 127. 



