1852,] SEDGWICK ON THE LOWER PALEOZOIC ROCKS. 139 



fossils from the Coniston (or Brathay) flags I find the following : — 

 1. Cardiola. 2. Creseis {Orthoceras). 3. harge Orthocei'atites. 

 4. Graptolites Lude?isis (now G. priodon). 5. Astrcea ananas. 6. 

 Asaphus {Phacops) caudatus. 7. Atrypa compressa.'^ I may re- 

 mark, that when this list was examined and determined, these flags 

 were regarded as upper Silurian, and nearly on the parallel of the 

 Wenlock shale. " Let us now (adds Mr. Salter) examine these 

 fossils with a view of putting them in the upper Bala groups. I 

 should not now call them upper Silurian. . . . For Cardiola (1.) oc- 

 curs in Llandeilo flags at Builth ;. Creseis {Orthoceras) (2.) is plentiful 

 in Llandeilo flags; large Orthoceratites (3.), species not named, 

 prove nothing, and large smooth species, from what we know of the 

 Scotch series, are quite as characteristic of older rocks ; Graptolites 

 priodon (4.) is known to be plentiful in Llandeilo flags ; Astrcea 

 ananas (.5.) is also found in Coniston limestone ; Phacops obtusicau- 

 datus (6.) is described, in my appendix to your second Fasciculus 

 of the 'Cambridge Palaeozoic Fossils' (now in the press), as a per- 

 fectly distinct species, allied to Phacops caudatus ; Atrypa compressa 

 (J.) I do not now know. So you see every quoted species may be as 

 well, nay better, interpreted as belonging to Bala beds. ..." 



He then shortly notices the very meagre list of fossils derived from 

 the Coniston grits, viz. Cardiola and Orthoceratites ; and he adds, 

 " As Cardiola is so plentiful in the Coniston flags, no wonder it 

 should often occur in the grits ; and as for the Orthoceratites, they 

 prove nothing against the grits being Caradoc. The species, if named 

 rightly, is O. Ibex, and this occurs in the Coniston limestone ; but 

 the grit specimens are not good. . . . We now know how barren the 

 Caradoc sandstone often is ; and that (in Westmoreland and Cum- 

 berland) it should contain some fossils from the beds below, is no 

 wonder." The previous quotations from Mr. Salter's letter are given 

 (as far as possible) word for word ; and are perfectly to the point. 



To avoid all doubt, I sent the previous list of seven species, with 

 an additional query respecting Orthoceras Ibex, to Professor M'Coy, 

 who is now in Ireland, in order that he might inform me how he had 

 determined their geological place in the second Fasciculus of the 

 * Cambridge Palaeozoic Fossils.' The proof-sheets of this work have 

 for several months been under revision ; the plates and catalogues 

 were finished during the past summer ; and the whole work, but for 

 the, perhaps unavoidable, delays of the University Press, would before 

 this time have been published. 



His reply (dated Nov. 12, 1851) contains the following critical 

 remarks: — •" 1. As to Cardiola interrupta, you have it, from the 

 black shales north of Builth (Llandeilo group), in your museum. 

 2. Of the other Coniston flag fossils, Creseis (so called) is common 

 enough in the same black shales CCaradoc shale) . 3. Orthoceratites 

 prove nothing, the species being undetermined. 4. Graptolites Lu- 

 densis (not G. priodon) occurs from the Scotch graptolite- slate up 

 to the Ludlow. 5. Astrcea ananas (so named in your list) has no 

 generic or specific relation to that Wenlock species. It is a species 

 of Linne, Sarcinula organum (first described as British in ' Camb. 



