Geology,: Introductory, Descriptive, & Practical, Tom 1John Van Voorst, Paternoster Row., 1844 |
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abundant Ammonites animal appear argillaceous bands bones Brachiopoda Bradford clay calcareous carboniferous carboniferous system Cephalopoda chalk chapter character characteristic chiefly clay coal measures coal-field colour conglomerate considerable consist containing contemporaneous corals Cretaceous deposit described Devonian Devonshire district enamel England exhibited existing extensive extinct species extremely feet fins fish formation fossil remains fossiliferous fossils fragments genera genus Geol geological grauwacké grit Ichthyosaurus jaws length Lias lime lithological Ludlow magnesian limestone marls mass Megalosaurus micaceous millstone grit mineral mountain limestone Murchison nature Nautilus nearly newer observed occasionally Old red sandstone older rocks Oolitic organic remains overlying Paleozoic Paleozoic period peculiar plants plates portion remarkable reptiles resembling sand Saurians scales shales shell Silurian Silurian rocks Silurian system singular siphuncle slates specimens stone strata structure subdivisions surface tail teeth thickness tion upper beds Upper Silurian vegetable vertebræ vertebral column Wealden Wenlock whole
Popularne fragmenty
Strona 17 - Jorullo, the central one, was elevated 1600 feet above the plain, and continued burning, sending forth streams of basaltic lava till the month of February in the succeeding year. None of the other cones were less than 300 feet in height. Twenty years after the eruption, this spot was visited by Humboldt, who found around the base of the cones, and spreading from them as from a centre, a mass of matter 550 feet in height, extending over a space of four square miles, and sloping in all directions towards...
Strona 13 - In 1807, during the erection of the lighthouse, six large blocks of granite, which had been landed on the reef, were removed by the force of the sea, and thrown over a rising ledge to the distance of twelve or fifteen paces ; and an anchor, weighing about 22 cwt., was thrown up upon the rock.
Strona 75 - That the teeth may be adapted to tear flesh, they must be sharp, and they must be more or less so exactly according as they are likely to have more or less flesh to tear; while their bases must be strong in proportion to the quantity of bone and the magnitude of the bones they have to break. Every one of these circumstances, also, will have its effect on the development of all the parts which assist in moving the jaw. " That the claws may be able to seize the prey, there must be a certain amount...
Strona 398 - The Belemnite, having the advantage of its dense but well-balanced internal shell, must have exercised its power of swimming backwards and forwards, which it possessed in common with the modern Decapod Dibranchiata, with greater vigour and precision.
Strona 328 - ... stronger and thicker shells of nautili. ' This support is effected by causing the edges of the transverse plates to deviate from a simple curve into a variety of attenuated ramifications and undulating sutures. Nothing can be more beautiful than the sinuous windings of these sutures in many species, at their union with the exterior shell ; adorning it with a succession of most graceful forms, resembling festoons of foliage, and elegant embroidery. When these thin septa are converted into iron...
Strona 53 - ... the most fleeting, one would think, of all characteristics — and offering evidence of the brilliancy and beauty of creation at a time when man was not yet an inhabitant of the earth, and there seemed no one to appreciate beauties which we are, perhaps, too apt to think were called into existence only for our admiration."* ROCK SYSTEMS.
Strona 314 - Cheltenham, where the marlstone of Dumbleton Hill is crowded with interesting organic remains. It is made up of alternating layers of coloured clays and sands, which are occasionally calcareous, and of beds of impure limestone. " This part of the series is also represented in the north of England, where it has an average thickness of about 130 feet, and consists of •andy shales, of which the upper portions are distinguished by the presence of several bands of argillaceous irony nodules.
Strona 416 - ... to walk about like a bird, to perch on a tree, to climb rocks and cliffs, and possibly also to swim in the ocean. We have, therefore, in this singular genus an animal which, in all points of bony structure, from the teeth to the extremity of the nails, presents the characteristics of a reptile, being even perhaps covered with scaly armor, and which was also a true reptile in the important peculiarities of the structure of the heart and circulating organs.
Strona xx - De la Rive.— A Treatise on Electricity, in Theory and Practice. By A. DE LA RIVE, Professor in the Academy of Geneva.
Strona 10 - The total length of river flooded on this occasion could not be less than between five and six hundred miles, and the whole of the river courses were marked by the destruction of bridges, roads, crops, and buildings. Speaking of the river Nairn, Sir TD Lauder relates, in a detailed account of this flood, that a fragment of sandstone rock, fourteen feet long, three feet wide, and one foot thick, and which could not have weighed less than three tons, was carried down the river a distance of two hundred...