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



like reasoning, it also followed, that the grits, conglomerates, coarse 

 slates, &c., which ranged under the Denbigh flags on the north side 

 of the Holyhead Road, and then ran down almost to Conway, must 

 be Upper Silurian. The fossils of these rocks were examined, and 

 they were determined to be Upper Silurian. With one exception 

 (the quarry of Plas Madoc), they were few in number and ill-pre- 

 served ; and, as they belonged to a group like that of May Hill (above 

 alluded to), no wonder that they were called Upper Silurian. 



In my own unassisted examination of these rocks in 1831 and 1832, 

 I called the beds over the calcareous slates of Mallwyd, which ex- 

 tended in undulations to Can Office, Upper Cambrian ; and my 

 Upper Cambrian, as before stated, did include the Caradoc sandstone. 

 The grits, conglomerates, &c. under the Denbigh flags, I set down as 

 Caradoc, partly on what I was able to make of the fossil evidence ; 

 but mainly on the fact, that the beds in question seemed to overlie 

 my Cambrian series unconformably. My previous determination (in 

 1832) was right, and our new determination in 1843 was wrong. But 

 far be it from me to blame my friend Mr. Salter for it. He rightly 

 translated the rocks we saw into the Silurian tongue ; but that tongue 

 misled us both. In point of fact, we were attempting an impossi- 

 bility, — we were endeavouring to join my Upper Cambrian series, 

 which was rightty interpreted, to the lower beds of the Silurian series 

 which had been wrongly interpreted and shifted out of their true 

 place in the great continuous Cambrian sections. 



All my papers, of which there is any notice in our Proceedings, or 

 Journal, between 1843 and 1846, necessarily partake of the mistakes 

 to which I have just pointed. If the Bala limestone was a Caradoc 

 limestone, the Upper Cambrian system must vanish from my map. 

 I therefore adopted a new nomenclature in my paper in the first num- 

 ber of our Journal *. The whole series, Cambrian and lower Silu- 

 rian, I called Protozoic. The Upper Protozoic groups were on this 

 scheme the equivalents of the Lower Silurian rocJis. The Loiver Pro- 

 tozoic groups were what I had before called Lower Cambrian ; and 

 these groups were the only Cambrian series that remained in this new 

 scheme of nomenclature. But when I speak of my paper in the first 

 number of our Journal (and vol. iv. of the Proceedings), I speak in- 

 iaccurately. The paper is not mine, and I disclaim its authorship. It 

 is a condensed abstract, made by Mr. "Warburton (when President) of 

 two papers read by myself to this Society. This abstract was printed 

 while I was in residence at Norwich. I applied, again and again, for 

 a sight of the proof-sheets as they were passing through the press ; 

 but I applied in vain. The President refused my application, and 

 for what reason I never could divine. The abstract is, however, very 

 carefully made ; but from a want of a short running comment, which 

 I could have given in a few lines, it is hardly possible to make out 

 the comparative meaning of the sections ; and there are a few mis- 

 takes introduced into them, perhaps not worth noticing in this place. 

 But the map, with its explanation of the colours, plainly shows that 

 Mr. "Warburton did not comprehend the very drift and object of my 

 * See also Proc. Geol. Soc. vol. iv. p. 251-268, 



