Geological observations on the volcanic islands, visited during the voyage of H.M.S. Beagle, together with some brief notices on the geology of Australia and the Cape of Good Hope. Being the second part of the Geology of the voyage of the Beagle under the command of Capt. Fitzroy, R.N. during the years 1832 to 1836 / [Charles Darwin].

  • Darwin, Charles, 1809-1882.
Date:
1844
Catalogue details

Licence: Public Domain Mark

Credit: Geological observations on the volcanic islands, visited during the voyage of H.M.S. Beagle, together with some brief notices on the geology of Australia and the Cape of Good Hope. Being the second part of the Geology of the voyage of the Beagle under the command of Capt. Fitzroy, R.N. during the years 1832 to 1836 / [Charles Darwin]. Source: Wellcome Collection.

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    2. Stenopora oyata, sp. n. Branched, branches oval; tubes relatively short, divergence great ; mouths round; contractions or irregularities of growth nu- merous. The characters of this species have been very imperfectly ascer- tained. The branches are not uniformly oval, even in apparently the same fragment. The tubes diverged rapidly along the line of the major axis, and had but a very limited vertical growth. Their casts exhibit a rapid succession of irregularities of development. The mouths, as far as they can be determined, were round or slightly oval, and the dividing, tuberculated ridges sharp; but in consequence of the outer surface not being exposed, their perfect characters, and the changes incidental upon growth, could not be ascertained. The coral is imbedded in a dark gray limestone. 1. Fenestella ampla, sp. n. Cup-shaped ; celluliferous surface internal; branches dichoti- mous, broad, flat, thin ; meshes oval; rows of cells numerous, rarely limited to two, alternate ; transverse connecting processes sometimes cellular; inner layer of non-cellular surface very fibrous ; external layer very granular, non-fibrous ; gemmu- liferous vesicle ? small. Some of the casts of this coral have a general resemblance to Fenestella polyporata, as represented in Captain Portlock’s Report on the Geology of Londonderry, PI. XXII. A. fig. 1 a, Id; but there is no agreement between the Yan Diemen's Land fossil, and the structure of that species as given in PI. XXII. figure 3. of the same work, or in Mr. Phillips’ original figures, Geology of Yorkshire, Part 2, PI. I. figures 19, 20. A general resemblance also exists between Fenestella ampla and a coral obtained by Mr. Murchison from the carboniferous limestone of Kossatchi Datchi, on the eastern flank of the Ural mountains, but there is again a marked difference in structural details. Fenestella ampla attained considerable dimensions, fragments ap- parently of one specimen covering an area of 4| inches by 3 inches; andjt displays considerable massiveness of outline, the branches at the points where they dichotimose often exceeding the tenth of an inch in breadth. M 2