136 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Feb. 25, 



that the gold-fields of nature, however rich along certain zones, were 

 necessarily limited by such conditions. 



Note. — Having above given the date of the publication in vvhich I compared the 

 " Australian Cordillera," then so named by me (1844), with the Ural Mountains, 

 and that of my invitation to the Cornish miners to work for gold in that Cordillera 

 (1846), I beg to state that English geologists are unacquainted with any other 

 printed documents relating to Australian gold, excepting my own, anterior to a 

 notice, by Mr. Clarke, of September 1847, in the Sydney Herald. That com- 

 parison of his of Australia with the Ural was, it will be observed, three years and 

 four months after my publication on the same topic. His letter to me, an extract 

 from which I gave in the Quarterly Review of September 1850, was long subse- 

 quent to his notice of 1847. — [R.I.M.] 



February 25, 1852. 

 The following communication was read : — 



On the Classification and Nomenclature of the Lower Pa- 

 leozoic Rocks of England and Wales. By the Rev. Prof. 

 Sedgwick, A.M., F.R.S., G.S. 



§ 1. Cumbrian Series, 



In a former paper*, of which this is a continuation, I endeavoured to 

 ascertain the geological place of some groups of slate-rocks which are 

 seen in certain parts of Westmoreland and Yorkshire near the base 

 of the carboniferous limestone ; and I endeavoured to show that the 

 several groups which appeared on one or more of the sections were the 

 equivalents, respectively, of the Coniston limestone, ih^Coniston flag- 

 stone, the Coniston grits, and the Ireleth slates, &c. These equiva- 

 lents are well known, having been described by myself in former pub- 

 lished papers f. But a new question may arise respecting their true 

 place in the lower divisions of the whole palaeozoic system. In the 

 Cumbrian cluster of mountains, the whole series of deposits below the 

 Old Red Sandstone has been long separated into three great physical 

 subdivisions ; the lowest of which included the Skiddaw slate ; the 

 middle was represented by a vast development of green slate and por- 

 phyry ; while the highest included all the rocks of Westmoreland and 

 Lancashire, from the calcareous slates of Coniston to the highest beds 

 that were overlaid by the old red conglomerates, or were covered by 

 the beds of the great Scar-limestone. Such were Mr. J. Otley's three 

 physical groups ; and they were adopted as the basis of classification 

 by myself and others who followed him. 



So soon as I became acquainted (in 1831 and 1832) with the rocks 



* Quart. Journ. Geol. Soc. vol. viii. pp. 35-54. 



t See papers, Proc. Geol. Soc. vol. i. p. 399 {Cumbria); ibid. vol. ii. p. 675 

 {Cumbria and N. Wales); ibid. vol. iii. p. 541 {Cumbria and N. Wales); ibid. 

 vol. iv. p. 212 {N. Wales) ; ibid. p. 251 {N. Wales) ; ibid. p. 576 {N. Wales and 

 Cumbria) ; Quart. Journ. Geol. Soc. vol. i. p. 5 {Cumbria) ; ibid. p. 442 {N. Wales 

 and Cumbria) ; ibid. vol. ii. p. 106 {Cumbria) ; ibid. vol. iii. p. 133 (iV. IVales and 

 Cumbria) ; ibid. vol. iv. p. 216 {Cumbria). 



