Vol. 58.] ASSOCIATED BEDS OF THE MALVERN HILLS. 129 
Lower Tremadoc, and in the Arenig.' This form, moreover, is 
represented by an allied species (Cheirurus foveolatus, Ang.) in the 
Upper Ceratopyge-bed of Norway.” Niobe (Ptychocheilus) peltata, 
Salter, of the Tremadoc and Arenig of Wales, is also represented in 
the Bronsil Shales by an allied or identical species. These facts 
leave no doubt that the Bronsil Shales contain a typical Huloma- 
Niobe fauna, and that, at all events in the main, they correspond to 
the Lower Tremadoc of North Wales. The occurrence of Cheirurus 
Frederici may, however, indicate that a zone as high up as the 
passage-beds between the Lower and Upper Tremadoc is represented. 
Furthermore, it is possible that the highest Bronsil Shales, which 
are largely concealed, and have hitherto yielded no recognizable 
species, may belong to the Upper Tremadoc. 
The occurrence of Dictyonema sociale, Salter, in company with a 
definite Tremadoc fauna is paralleled elsewhere. The Dictyonenu- 
shales of North Wales were grouped in 1867 by Belt,* and in 1881 
by Prof. Lapworth, with the Lower Tremadoc, rather than with 
Dolgelly Beds, or Upper Lingula-Flags.* It is true that some of 
the beds containing Dictyonema sociale have been placed by Salter 
& Etheridge in the Upper Zingula-Flags’; but it would appear 
that, with one doubtful exception, the fossils recorded as accom- 
panying Dictyonema sociale are of Tremadoc type. They include 
Lingulella lepis, Salt.," Symphysurus (Psilocephalus) «nnotatus, Salt., 
Niohe Homfrayi, Salt., and ‘ Ogygia’ sp.” ; and in such instances 
the beds have been referred to the Tremadoc. On the other hand, 
Dictyonema sociale is recorded from dark slates which have been 
termed ‘ Upper Lingula-Flags.’ The characteristic ‘ Upper Langula- 
Flag’ fossils, such as Spherophthalmus alatus and Peltura scarabe- 
oides, however, appear to occur in the lower part of the dark band ; 
and it is expressly stated that Dictyonema sociale is found only in 
the uppermost beds, at the point where the black slates of the 
“Upper Lingula-Flags’ give place to the greyer overlying beds.° 
Mr. P. Lake & Prof. 8. H. Reynolds, moreover, find in the neigh- 
bourhood of Dolgelly the zone of Dictyonema sociale in dark slates 
well above the widely-spread band of black and dark slates (‘ Upper 
Lingula-F lags’) which contain the Doilgelly fauna; they have ob- 
tained from the black slates themselves Acrotreta Sabrine, Call., 
a characteristic Shineton and Malvern form. The evidence, then, 
appears to be in favour of including all the slates of North Wales 
Mem. Geol. Surv. Gt. Brit. vol. ii, 2nd ed. (1881) pp. 859 & 521. 
Nyt Mag. for Naturvidensk. vol. xxxvi (1898) p. 233. 
Geol. Mag. 1867, p. 542. 
Ibid. 1881, p. 320. 
> Mem. Geol. Surv. Gt. Brit. vol. iii, 2nd ed. (1881) pp. 86, 344, 349, 350, 
o04, & 536. ° bid. p. 348. 
* Lake & Reynolds, Quart. Journ. Geol. Soe. vol. lii (1896) p. 514. 
* Mem. Geol. Surv. Gt. Brit. vol. ili, 2nd ed. (1881) pp. 86 & 358; see also 
pp. 91, 344, 354, & 356. 
° Thid. pp. 86, 349, & 536. It may be seen, too, in the list (op. cit. p. 350) of 
localities for fossils of the ‘Upper Lingula-Flags’ that when Dictyonema 
sociale is recorded, it does not appear in association with the remaining fossils. 
Q: J.G.8) Ne:229. K 
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