and the Palceozoic System of England, 497 



amply illustrated by sections, in a paper read before the Geolo- 

 gical Society in 1838 (Proceedings, vol. ii. p. 679, 680). The 

 paper wac not published, for the simple reason that I could not 

 bring the upper portion of the sections into any intelligible coor- 

 dination with the lower groups of the "Silurian System :'' and I 

 quote the sections in this place only to prove that the Cambrian 

 series (of course adopting by anticipation the names afterwards 

 agreed upon) was, as to its great physical framework, as well 

 known by me in 1832 as it is now*; the separation between 

 the upper and lower divisions of the series being then drawn at 

 the base of the Bala limestone. 



I had not (in 1832) connected the upper Bala beds of Corwen 

 with those of Glyn Ceiriog by a complete traverse, but there could 

 be little or no doubt of their continuity and identity. I did, how- 

 ever, make some elaborate sections to the east of the Berwyns, 

 connecting the fossiliferous group of Glyn Ceiriog with that of 

 Meifod. They are separated by a rude irregular saddle of old 

 Cambrian rocks; each of them is overlaid by what was even then 

 called Wenlock shale, and their fossils are identical. There can 

 be no doubt that, considering the facts by themselves, any ob- 

 server would have connected the Meifod beds, the Glyn Ceiriog 

 beds and the upper Bala beds into one geological group ; and if 

 this be done, the great Cambrian series becomes complete with- 

 out blemish or hindrance. 



Finally, in 1832. I made traverses from the south flank of 

 Cader Idris as far as the banks of the Dyfi, but with little 

 profit ; for I failed to find the object I was seeking, viz. the Bala 

 limestone, which was the hoped-for base for another summer^s 

 work. One positive result was, I believe, gained. The first 

 dark and impure slate group overlying the Cader Idris system, 

 was identified with a corresponding group (Upper Cambrian 

 a (1), supra, p. 362) of the Arenig section ; and a similar group 

 overlies the old slates and porphyries of Pembrokeshire, as I 



* The dark earthy slates of Carnarvon were at first left by me in a doubtful 

 place ; but I was the first observer who put them in their right place and 

 made them the equivalents of the Tremadoc slate {supra, p. 362). When 

 the Lingula was found by Mr. Davis near Tremadoc, I knew its sectional 

 place in the series, and I had no difficulty whatsoever in afterguards follow- 

 ing it from Tremadoc to Cader Idris. Some time afterwards I wrote to a 

 friend in the Government Survey (either Mr. Salter or Mr. Jukes), and 

 stated that if my conception of the structiu-e of the Carnarvon chain was 

 right, the Lingula beds ought to be found immediately over the Harlech 

 grits, which cap the great slate quarry of Nant Francon. The reply was, 

 that they had found the Lingula in the beds referred to. I mention these 

 facts, not in the way of boasting, but to save myself from the imputation 

 of having dressed up the Cambrian series at a period long after 1832. My 

 Cambrian sections were right, or very nearly right, from the beginning ; 

 and there was no great mistake in my sections of 1838. 



