174 PROCEEDINGS OF THE GEOLOGICAL. SOCIETY. 



Historical Retrospect. — (1831.) In the year 1831 Professor Sedg- 

 wick and myself commenced, but without any concert, our respective 

 surveys, he in North Wales, and myself along the Welsh and English 

 borders. In that year he published no notice of his observations ; but 

 on my part, being then President of the Geological Society, I laid 

 before the first meeting of the British Association at York (Sept. 1831) 

 a coloured geological map representing the succession of what I then 

 termed the '' Transition Rocks, Old Red Sandstone, and Carboniferous 

 Limestone on the borders of Wales*." My contemporaries (Mr. 

 Greenough, Professor Phillips, and others) who were present will 

 recollect, that I then explained the discovery of an infraposition of 

 certain beds of fossiliferous grey wacke to the lowest member of the 

 Old Red Sandstone, and described their general range from the banks 

 of the Wye to those of the Teme near Ludlow, or to that tract where 

 the Rev. T. T. Lewis afterwards rendered me signal assistance. The 

 discovery was made in consequence of a resolution of my own to en- 

 deavour to work out, if possible, a descending order beneath that 

 geological horizon to which previous researches had carried it. This 

 was the origin of a series of labours, the results of which were in suc- 

 cessive years communicated to the Geological Society and registered 

 in its Proceedings, and which ended, in the year 1835, in my pro- 

 posal of the "Silurian System." 



(1832.) Professor Sedgwick's first communication to the public on 

 the structure of North Wales was made to the British Association at 

 its second Meeting in 1832, and is entitled "A Verbal Account of 

 the Geology of Caernarvonshire," which is reported in a few lines of 

 type, in which no allusion is made to an order of succession in rela- 

 tion to any known stratum, nor to rocks characterized by any organic 

 remains. 



(1833.) In the years 1833 and 1834 Professor Sedgwick published 

 nothing, as far as I know, on the subject of Wales, whilst in that 

 period I produced before the Geological Society several memoirs, de- 

 tailed sections, many sheets of the Ordnance Survey coloured by 

 myself in the field, and copious organic remains, by which in February 

 1833 a first general view was adopted oi four fossiliferous forma- 

 tions, underlaid by a great mass of unfossiliferous greywackef . 



(1834.) In January 1834 the previous view was sustained, im- 

 proved, enlarged, and corrected in some details, the formations be- 

 neath the Old Red Sandstone being termed in descending order 

 Ludlow Rocks, Wenlock and Dudley Rocks, Horderley and May Hill 

 Rocks (afterwards named Caradoc), Builth and Llandeilo Flags, the 

 whole underlaid by the unfossiliferous grey wacke of the Longmynd:|:. 

 Let me here remark, that this my earliest corrected classification, 

 and before the word " Silurian " was applied to it, is what has been 

 eventually sustained as the true order of nature in many parts of 

 the world as well as in Britain. 



(1835.) Having extended my researches from the counties of 



* Report of the British Association, vol. i. p. 91. 

 t Proceed. Geol. Soc. vol. i. p. 470 et seq. 

 t Proceed. Geol. Soc. vol. ii. p. 11. 



