RvAN AND Hai.lissv — Some New Fossils from Braij HemL 249 



centre and the margin of the disk, a concentric muscular system in the sub- 

 umbrella surface, and a system of radial canals extending from a central 

 ring-canal to the margin of the umbrella. A large specimen found in 

 these beds measured 12 cm. across the disc, but the majority were of smaller 

 dimensions. In the later specimens obtained by us, which are about 7 em. 

 diamete]', one seems to recognize the same general structure as above 

 described ; and we venture provisionally to class them under the genus 

 Eldonia, giving them also a provisional specific name, antonii,' till later com- 

 parison of these or better specimens with Walcott's compels us to change. 



As Walcott found a Crustacean fauna associated with the Holo- 

 thurians in the same beds of the Middle Cambrian of British Columbia, 

 we are content, pending better specimens, to abide by Mr. Eeed's opinion, 

 that the fossil represented by fig. 3, Plate XXIII, is part of the head-shield of 

 a large trilobite. The difficulty, of course, is in the curious radial striation 

 adjudged by Mr. Reed a secondary structure. 



Given that the fossils represented in figs. 5, 6, and 8 are similar to Walcott's 

 from the Middle Cambrian — and in this we have much support — and seeing 

 that other fragmentary specimens found by us at Bray Head also point to a 

 fauna like that obtained from the Burgess Shale deposits of British Columbia, 

 there is at least a high degree of probability that the green and purple 

 slates of Bray must be referred to the same horizon of the Middle Cambrian. 



Bibliography. 



Baily, William Hellier (1857) : 



Explanatory Memoir to accompany Sheets 121 and 130. Mem. Geol. 

 Survey of Ireland, p. 16 et seq. 1869. 

 Cole, G.A.J. (1901): 



Recent Observations on Oldhamia and Histioderma. Irish Naturalist, 

 vol. X, p. 81. 



(1908) : 



General Geology and Scenery (round Dublin). British Assoc. Handbook 

 to the Dublin District, p. 5. 

 Du NoYER, G. V. (1867) : 



Explanatory Memoir to accompany Sheets 121 and 130. Mem. Geol. 

 Survey of Ireland. 121 and 130, p. 23 et seq. 1869. 

 Forbes, Edward (1848) : 



On Oldhamia, a New Genus of Silurian Fossils. Journ. Geol. Soc. 

 Dublin, vol. iv, p. 20. 



' After a friend of one of ilie uuthor^. 



