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PROCEEDINGS OE THE GEOLOGICAL SOCIETY. 



mations of North and South Wales. The portion of the memoir by 

 Prof. Ramsay devoted to' the Caradoc is of necessity large, arising 

 from the extent, magnitude, and importance of the Caradoc rocks 

 as developed in North and South Wales, Westmoreland, Ireland, 

 and Scotland, I therefore, as in the case of the older groups, com- 

 pare or attempt to correlate other portions of Britain with the 

 typical area in Wales, so as to show the present aspect or distribu- 

 tion of the Caradoc fauna, which is so largely developed in the 

 British Islands. To devote much space to the purely geological 

 aspect of the Caradoc would be needless under present circum- 

 stances, as so much has already been done by able observers in the 

 pages of our Journal, as well as in the exhaustive memoir on North 

 Wales by Prof. Ramsay. My tabular results in the appendix to the 

 above memoir, relative to the distribution of the Caradoc fossils both 

 in time and space, will, when published, embody almost all the in- 

 formation known. The result, however, will be referred to here, as 

 being a complete analysis of the 600 species. It is scarcely neces- 

 sary for me to discuss the views of authors as to very minute sub- 

 divisions of the Caradoc group in any given area or under any 

 peculiar condition ; such will always arise under critical examina- 

 tion, extended knowledge, or constant research ; and large as we know 

 the fauna to be, owing to the rocks being so extensively worked in 

 the days of Sedgwick and Murchison, and through the long-con- 

 tinued labours of the Geological Survey, yet many of the zoological 

 groups are still being added to. This is notably the case with the 

 elaborate memoir upon the Grirvan fossils by Prof. A. Nicholson and 

 Mr. Etheridge, jun., the first volume of which, containiug this 

 addition to our knowledge of the Caradoc fauna of Scotland, is just 

 completed and published. In this work the authors describe 41 

 genera and 65 species, many of which are new. Perhaps, with the 

 exception of Mr. Lapworth's paper on the Graptolites of the Moffat 

 series at Girvan and Glenkiln* (mostly Lower-Bala or Llandeilo 

 forms) no more important addition to our knowledge of the Caradoc 

 fauna has been made siuce M'Coy completed his great work upon 

 the British Palaeozoic fossils. 



The legends attached to the published maps of the Geological Survey, 

 and the explanation of the colours employed to designate the horizons 

 or formations surveyed, show that no attempt was made by the Survey 

 to divide the Caradoc rocks into subgroups, or into Lower, Middle, and 

 Upper Caradoc or Bala ; neither does Prof. Ramsay, in that part of 

 his memoir devoted to the Caradoc rocks, attempt any subdivision, 

 but masses the whole group between the top of the Llandeilo and 

 the overlying Llandovery. In the Catalogue of the Cambrian and 

 Silurian fossils in the Woodwardian Museum, Cambridge, Prof. 

 Sedgwick has divided the Bala beds into three subgroups, placing 

 them in his Upper Cambrian stage (the Cambro-Silurian of some 

 authors), the Lower Silurian of Murchison. The grouping adopted 

 in this catalogue is such as to eliminate the true Llandeilo fossils, 



* Quart. Journ. Geol. Soc. vol. xxxiv. pp. 249-346. 



