Published online by Cambridge University Press: 01 May 2009
Specimens of chert-rock from the Productus-chert division of the Permo-Carboniferous series of Spitzbergen are shown to consist largely of detached siliceous sponge spicules, thus indicating the probable derivation of this rock from the skeletal remains of these organisms. The chert is of the same character as that of the Yoredale beds of the British Isles, and it occurs on the same relative geological horizon. The Productus-chert division has a thickness on Axel's Island of 376 m., of which 265 m. are chert, and 111 m. dark siliceous schists, likewise containing sponge remains, but less abundantly than the chert. The chert had previously been regarded as connected in some way with the igneous rocks of the island.
page 241 note 1 Dec. III. Vol. IV. pp. 435–446.
page 241 note 2 Ueber Permo-Carbon-Schwämme von Spitzbergen, Kongl. Svenska Vetensk.Akad. Handl. Bd. 21, No. 1, pp. 1–18, taf. ii. (1884).
page 243 note 1 Anmärkningar om Permfossil från Spetsbergen; Bihang till K. Svenska Vet. Akad. Handb. Bd. 13, Afd. iv. No. 1, pp. 1–26 (1887). Cf. Geol. Mag. March, 1888, p. 131.
page 245 note 1 British Fossil Sponges, pt. i. pl. v. fig. 1b, Pal. Soc. vol. for 1886.
page 245 note 2 British Patæzoic Sponges, pt. ii. Pal. Soc. vol. for 1887, p. 100.
page 245 note 3 Sketch of the Geology of Ice Sound and Bell Sound, Spitzbergen, , Geol. Mag. Dec. II. Vol. III. 1876, p. 66.Google Scholar
page 246 note 1 A somewhat similar origin was attributed to a band of flinty or horny rock in theCarboniferous Limestone of Glencart, Ualry, Ayrshire, by my friend Mr. John Young, F.G.S., who regarded the silica as deposited chemically by heated waters from spriDgsconnected with volcanic vents in the neighbourhood (Proc. Nat. Hist. Soc. Glasgow, April 25. 1882, p. 237). Since hearing my paper on the organic origin of the IrishCarboniferous chert, Mr. Young examined sections of this flinty band under themicroscope, and he has informed me that it is crowded with minute sponge-spicules, sothat no doubt of its origin from these organisms can be entertained.
page 248 note 1 Loc. cit. p. 7.
page 248 note 2 They are present in seven out of ten slides of P. arcticus, in both of the slides of P. verrucosus, in two out of three slides of the var. macropora, and in two out of three slides of the var. latituba, which were sent to me by Prof. Lindstrtini.
page 250 note 1 As already mentioned, the spicules in Pemmntifes latituba differ in form, andthey are more slender than in the other species described.