] INTRODUCTION. 
passing through the press he refused (on my repeated application) to let me see a single 
proof-sheet! 1 believe that he did his very best with my sections; though in their illus- 
tration he adopted a complicated symbolical system of notation which is painful to follow, 
and of which I never have made myself master. In the reduction of my map he made 
mistakes both of omission and commission*: but in naming the groups delineated upon it, 
without any warrant from myself he tampered with my nomenclature, so as to bring it into 
agreement with that scheme which, unknown to myself, was newly adopted by Murchison, 
and to which I have before alluded. It was a scheme which utterly excluded me from 
any share in the nomenclature of the older rocks of Wales. It was a scheme in which my 
friend claimed Wales as his own, though he had only touched its outskirts, and though 
he had absolutely mistaken the geological relations of every part, he had touched, that 
was below the Wenlock group. 
To avoid all possible wrangling about the words Cambrian and Silurian, I had pro- 
posed to designate all the groups below the Wenlock, by the name Protozoic (a name 
originally proposed, nearly in the same sense, by Murchison himself). Where the division 
could be made upon the map of Wales, the Protozoic series was to be separated into 
two divisions—upper and lower—by a line on the parallel of the Bala limestone sub-group. 
All above the Bala limestone was to be Cambro-Silurian—all below was to be Cambrian. 
Yet in Mr Warburton’s reduction of my map, Protozoic is made the equivalent of Lower 
Silurian! 1 cannot believe that this was done by oversight. It was an unwarrantable 
* Many critical parts of North Wales were mapped by Mr Salter and myself in as much detail as is given in the 
map of the Government Survey. We traced, laid down, and followed on their whole line of strike towards the North, the 
two bands of limestone below Llanwddyn (distinctly shewing the Bala limestone repeated by a fault). The second band is 
left out in Mr Warburton’s reduced map and sections. Our maps were, for several weeks together, suspended in the 
Geological Society’s meeting-room; and they were some months in Mr Warburton’s possession. So also were my sections of 
Carnarvonshire and Cader Idris, &c. which had been exhibited in 1838. His reduced map was not at all taken from the 
maps above-mentioned; but exclusively from a bold enlarged sketch of North Wales made (for illustration of the papers 
while read) by my friend Mr S. Woodward; and upon which I had roughly drawn the principal demarcations, the lines 
of strike, and the other conditions of structure that seemed essential. - 
In 1832 I had followed the Glyn Diffws limestone (described in the first section of Mr Warburton’s abridgment) 
towards Bala, and identified it with the Bala limestone; and so it is represented, by the help of dotted lines, on my field- 
map. But in 1843 I followed this broken calcareous band along with Mr Salter, much more completely than I had done 
in 1832; and it appeared to me, that on physical evidence (and so it was stated in my paper, though the passage is very 
obscurely indicated in the abridgment) the Rhewlas limestone must be identical with that of Glyn Diffws or Bala. Nor on 
this supposition should I have made any difficulty in the enormous shift of the Bala limestone, from the old Rhewlas lime- 
works to Rhewedog, which is considerably to the east of the Bala lake. For the intersecting valley of the Tryweryn 
was a feature which, on the analogy of the Coniston limestone, naturally suggested the expectation of a great fault, 
and consequent shift of the Bala limestone. (Z'ransactions of the Geol. Soc. 2nd Series, Vol. IV. pp. 50—53 ) Why then 
did I not act on this opinion? Because, in the year preceding, Mr Sharpe had discovered a limestone (undoubtedly con- 
nected with the Rhewlas beds) which he appeared to have traced considerably to the west of the Bala lake; and which 
he represented (with no hint that the representation was hypothetical) in a section from great Arenig to the Berwyns. 
We sought this limestone more than once; and, of course, could not find what did not exist. I have no doubt that 
Mr Salter’s judgment respecting the Rhewlas fossils was somewhat influenced by a belief (derived from the section above 
mentioned) that they were obtained from a bed that was far below the Bala limestone; but I take shame to myself for 
haying surrendered my faith, in what I thought good physical evidence, to a belief in a section which I could not verify. 
(See Proceedings of the Geol. Soc. Vol. Iv. p. 253 ) 
