Memoirs of the Geological Survey of Great Britain and the Museum of Economic Geology in London, Band 2,Teil 1H.M. Stationery Office, 1848 |
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Abberley District Woolhope Abberley Hills anticlinal appear Aymestry rock bands beds Builth Builth District Llandilo calcareous Caradoc sandstone Cefn coal conglomerate convex corals deposits District Abberley District District Builth District District Llandilo District District Malvern District District Marloes District District May Hill District Usk District District Woolhope District Ditto Dormington Dormington Wood eastern Eastnor feet felspar fossiliferous fossils Freshwater East furrows Geological Golden Grove gray Haverfordwest Haverfordwest District hornblende laminated Ledbury Leptæna Llanbadoc Malvern District Abberley Malvern Hills Marloes Bay mass micaceous miles Mill Murchison occur Old Red Sandstone ORTHIS Palæozoic Phillips quarries R. I. Murchison red marls REF.-Murchison REF.-Palæontological Appendix REF.-Pl ridge Salter shales shell Shucknall Silurian Silurian strata South species specimens striæ surface syenite Syst thickness Tortworth trap Upper Ludlow Usk Castle valve ventral vertical Wenlock Wenlock limestone western side Woolhope limestone Worcester Beacon Worcestershire Beacon
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Seite 4 - On the Upper Formations of the New Red Sandstone System in Gloucestershire, Worcestershire, and Warwickshire ; showing that the Red or Saliferous Marls, including a peculiar Zone of Sandstone, represent the
Seite 337 - A very usual character of this genus [Proetuti] is the possession of a strong tubercle, terminating the neck segment on each side, and nearly separated from it. Burmeister, however, in his second edition, has considered the species having this thickening, and the obscure glabella furrows more strongly marked, as forming a distinct genus, which he calls JSonia. McCoy had anticipated him by a few months in the name Forbesia, without referring to Proetut.
Seite 75 - ... there is really no firm and hard boundary between the lower and upper Silurian periods ; for both by mineral and by organic evidence, the characteristics of these periods are found to overpass each other, the older characters re-appearing within the later deposits, and the later characters showing themselves amidst the earlier deposits. As a general result, it is quite evident that the successive changes of organic forms, as they are exhibited to us in the successive groups of strata, are not...
Seite 56 - They are particularly interesting, as connected with phenomena quite different from those which appear along the great chain of the Malverns, being, in fact, porphyritic and greenstone masses, which, erupted from below, have flowed in limited streams over the surface of the black shales.
Seite 220 - In a general sense the whole series of strata in the district from St. Bride's Bay to a point east of Caermarthen may be regarded as Lower Silurian." — p. 220. Of Goldengrove, near Llandilo, he says (p. 221) : — " In a general sense this series may be regarded as containing peculiar types, both of Upper and Lower Silurian, which cannot be...
Seite 157 - ... untraceable ; that instead of it, especially on the south side, a great abundance of angularly intersecting divisional planes occur, so as to produce prismatic structures perpendicular to the plane of the dyke. Further, we observe, parallel to the dyke, to a distance of 30 or more feet from it, several very long, very straight, nearly vertical joints, continuous through all the beds, without any sign of vertical displacement, or any mark of lateral disturbance, unless the appearance of broad...
Seite 156 - Fig. 4O. a space of 30 feet on the north and 17 feet on the south of the dyke, the sandstones and marls are changed in hardness, texture and structure, so that for these breadths they are excavated with the trap ; and from their density, hardness, and resemblance to basalt, amygdaloid or porphyry, may be easily mistaken for primeval rocks of fusion. They have been literally baked under pressure, not roasted with freedom of access and escape for volatile matter.
Seite 156 - For a space of 30 feet on the north, and 17 feet on the south of the dyke, the sandstones and marls are changed in hardness, texture, and structure, so that for these breadths they are excavated with the trap; and, from their density, hardness, and resemblance to basalt, amygdaloid, or porphyry, may be easily mistaken for genuine rocks of fusion. They have been literally baked under pressure, not roasted with freedom of access and escape for volatile matter.
Seite 67 - The next thing to determine was the position of this conglomerate in relation to the ridge of syenitic rocks amongst the detritus of which its fragments lay. This was difficult. The abundance of detritus on all the slopes is so great as to conceal for the most part the junction of the stratified and unstratified rocks. The loose shelly pieces we found abundantly for fully one third of a mile along the mountain side, and at length the conglomerate rock itself was plainly seen adhering to the extreme...
Seite 195 - Caradoc period. By the same rule the Tortworth Traps are of the Caradoc period, and belong to what is now a large class of igneous products, much studied by Professor Sedgwick in North Wales, and familiar to the members of the Geological Survey in South Wales. They are, in fact contemporaneously effused Traps, most probably the fruit of limited and repeated pressures on the interior liquid masses of the earth, followed by solidification at small depths below, or even in part at the surface of the...