424 II. Bolton — On the Genus Listr acanthus. 



VIII. — On the Occurrence of the Genus Listracaxtiius in tui: 

 English Coal-measures. 



By Herbert Boltox, F.R.S.E., 

 Assistant Keeper, Manchester Museum, Owens College. 



DURING the last few months two spines, or Ichthy odontites, 

 belonging to the genus IAstr acanthus, have come under my 

 observation. Since both are well-preserved specimens, and not 

 hitherto recorded from the English Coal-measures, some information 

 as to their appparance and stratigraphical position may be of interest. 



The genus Listr acanthus was formed by Newberry and Worthen 1 

 in 1870 to include small spines found in the Coal-measures of 

 Illinois. These spines are small flattened structures, curved back- 

 wards, and with the sides ornamented by longitudinal ridges. 

 The convex and concave margins are provided with acute spiny 

 denticles. 



Newberry and Worthen described only one species, L. hystrix 

 (torn, cit., p. 372, pi. ii, figs. 3, 3a), to which L. Hildrethi was 

 subsequently added by Newberry 2 from the Coal-measures of Ohio, 

 and L. Beyrichi 3 by A. von Konen from the Coal-measures of 

 Herborn, Nassau. An undescribed species is also recorded by 

 A. Smith Woodward 4 from the Calciferous Sandstone of East 

 Kilbride, Lanarkshire ; while others from the Upper Carboniferous 

 Limestone Series of Belgium are noted by L. G. de Koninck. 5 



The larger of the two Lancashire specimens was found by me 

 amongst the geological collections of the Royal Museum, Peel Park, 

 Salford, when I was engaged upon their rearrangement. Although 

 unlabelled, it fortunately happens that the spine lies upon the 

 broken surface of an ironstone nodule, and is associated with 

 Goniatites Listeri, G. atratus, Aviculopecten papyraceus, and numerous 

 small ostracods. Ironstone nodules of this chai'acter are restricted 

 in the Lancashire Coalfield to the roof of the Bullion or Upper Foot 

 Mine of the Lower Coal-measures ; hence the horizon of the specimen 

 can be exactly determined. The second and smaller specimen is the 

 property of Mr. Robert Cairns, of Ashton-under-Lyne, and was 

 obtained by him from the marine band of the Middle Coal-measures 

 in the River Tame at Dukinfield. It is enclosed in a nodule of 

 earthy ironstone, and is unaccompanied by other fossils. I remember 

 finding a third specimen ten years ago in the shales overlying the 

 Bullion Coal of the Lower Coal-measures of Bacup, but it has since 

 been lost. 



Both the specimens now to be described differ from the three 

 species hitherto defined, as well as from one another, but it is perhaps 

 hardly justifiable to found a species upon the smaller specimen. 



1 "Pal. Illinois," vol. iv, 1870, p. 371. 



2 Rep. Geol. Surv. Ohio, vol. ii, pt. 2, 1875, p. 56, pi. lix, fig. 6. 



3 Neues Jahrb. 1879, p. 341, pi. vii, fig. l. 



4 Catal. Foss. Fishes, B.M., pt. 2, 1891, p. 149. 



5 " Faune Calc. Carbf. Belg.," pt. 1, 1878, p. 75, pi. v, fig. 11. 



