﻿264 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 28, 



shape, and furnished the materials for a tabular view of the successive 

 appearances of fish, given in Mr. Hugh Miller's work, entitled ff Foot- 

 prints of the Creator." 



As the well-deserved reputation of this eloquent author will give a 

 wide currency to his book, it is desirable to explain the nature of the 

 evidence on which these statements rest, and I am the more called on 

 to do so, since for two of the instances above-mentioned, viz. with 

 regard to North and South Wales, I am indirectly responsible. 



During the summer of 1846 I was engaged in examining, for the 

 Geological Survey, the fossils along the Silurian frontier in South 

 Wales, and I had the pleasure of meeting Prof. Sedgwick at Llandeilo, 

 and visiting several of the localities with him. During one of his 

 excursions he obtained a slab of the Llandeilo limestone, upon which 

 there lay a compressed and tapering fossil, longitudinally ribbed, and 

 bearing so much general resemblance to the defensive fin-bone called 

 Onchus, that I at once named it so ; nor were we at that time disposed 

 to question its probability, since we were both labouring under the 

 mistaken impression that these flags occupied a higher position than 

 had been assigned them, and that they were but little below the 

 parallel of the Wenlock Shale. And in the winter of that year Prof. 

 Sedgwick advocated this view in a paper read before the Society, and 

 announced the discovery of " defences of fishes" in the Upper Llan- 

 deilo Flags of South Wales. 



During the same year the Geological Surveyors were at Bala, in 

 North Wales, examining the localities which had been noticed by Prof. 

 Sedgwick in his papers on that country, and making rough catalogues 

 on the spot of all the fossils met with. Amongst them occurred a 

 fragment, curved like some Onchi, and, like the Llandeilo one before 

 noticed, striated lengthwise. This fragment also was entered in our 

 rough catalogues as a fish-defence ! — the analogy of course being more 

 readily perceived from the fact of having only a few weeks before seen 

 what was believed to be an Ichthyolite from beds of the same age. 

 This specimen also, like the former one, was only cursorily examined. 

 It was, however, mentioned in conversation to Sir Roderick Murchi- 

 son, and, in a Memoir on the Classification of the older Rocks, 

 read before the Society January 1847, he used it as an argument for 

 the union of the fossiliferous rocks of North Wales with the Lower 

 Silurian*, — a point now perfectly established on other grounds. 



But, on examining in London the specimens collected at Bala, I 

 found that the supposed fish-spine was in reality half the rostral 

 shield of a Trilobite common there, the Illcenus Bavisii, and that its 

 resemblance to an Onchus was due merely to its being broken in half 

 and obscured by stone. 



The Bala fish being thus disposed of, the probability of the Llan- 

 deilo one being equally spurious became manifest ; and I was not at 

 all surprised to find it described last year by Prof. M'Coyf as a new 

 genus of Asteroid Zoophyte, probably allied to the " Glass-plant," 

 and under the name Pyritonema fasciculus. As Prof. M'Coy has 



* Quart. Journ. Geol. Soc. vol. iii. p. 176. 

 f Ann. & Mag. N. H. Ser. 2. vol. vi. p. 273. 



