The Quarterly Journal of the Geological Society of London

Copertina anteriore
Vols. 1-108 include Proceedings of the society (separately paged, beginning with v. 30)
 

Cosa dicono le persone - Scrivi una recensione

Nessuna recensione trovata nei soliti posti.

Altre edizioni - Visualizza tutto

Parole e frasi comuni

Brani popolari

Pagina 387 - ... than cherts. Chert beds are commonly associated in a nodular form with limestone strata: the novaculites on the other hand, occur in massive strata, usually presenting plane surfaces and having only thin layers of shale interbedded. Five or six hundred feet is the common thickness of the novaculite formation, which generally includes some flinty shales and soft shales or sandstones. The novaculites proper are the prominent members of the formation, however, and occur in massive beds from a few...
Pagina 5 - ... noted and discussed. The remains are abundant in, if not strictly confined to, the limits of a great unglaciated area in the north-western part of the North American continent ; whilst within the area which was covered by the great ice-mass which the author has described as the Cordilleran glacier, remains of the Mammoth are either entirely wanting or are very scarce. At the time of the existence of the Mammoth, the North American and Asiatic land was continuous ; for an elevation of the land...
Pagina 385 - ... agree with the conclusions drawn from the chemical analyses. Nothing but silica can be seen. The silica is present in minute irregular grains closely crowded together to form a dense ground mass.
Pagina 150 - England, whilst the upper unfossiliferous beds may be the equivalents of the Danian Beds. The strata are, on the whole, of shallow-water origin, and were deposited in shallow bays in the Upper Cretaceous sea of Southern and Central Europe, on the northern flanks of the Eastern Alps. Probably towards the close of Upper Cretaceous times the southern area of the Gosau District was cut off from the sea to form a lakebasin in which the upper unfossiliferous series was deposited. 2. "Artesian Borings at...
Pagina 547 - ... holding the mineral in solution. The reaction of such waters upon the potash-felspar of the sands, furnished by the disintegration of the crystalline rocks, would not lead to the deposition of free silica (as in the ordinary process of kaolinisation), because, while the potassium was taken up as a carbonate and carried away, the silica was also removed in solution, through combination with the sodium, to form sodium silicate. This last-named salt in solution would be readily decomposed by the...
Pagina 430 - ... ancestor towards the modern Crustacea. The trilobites then must have branched off laterally from this line either once or more than once, in times anterior to the primitive Apug, as forms specialized for creeping under the protection of a hard imbricated carapace.
Pagina 2 - Wild and exaggerated stories have found a place, even in official documents, in regard to fossil ivory. This is not uncommon in many parts of the valleys of the Yukon and Kuskoquim. It is usually found on the surface, not buried as in Siberia, and all that I have seen has been so much injured by the weather that it was of little commercial value. It is usually blackened, split, and so fragile as to break readily in pieces. A lake near Nushcrgak, the Inglutalik River, and the Kotlo River, are noted...
Pagina 478 - When a shirt, after being washed, is exposed in the open air to a temperature of 40° or 50° below zero, it is instantly rigidly frozen, and may be broken if violently bent. If agitated when in this condition by a strong wind, it makes a rustling noise like theatrical thunder. In an hour or two, however, or nearly as quickly as it would do if exposed to the sun in the moist climate of England, it dries and becomes limber.
Pagina 401 - ... explanation to account for the formation of the rock, and maintains that its peculiar characters are due to interbedded layers of vegetable matter, which decomposed and evolved carbonicacid gas and marsh-gas. This decomposition continued while several inches of new sediment were laid down, the result being that arborescent markings were produced along the lines taken by the escaping bubbles...
Pagina 8 - The speaker was of opinion that this ice had accumulated since the beds were laid down, and was not there when the mammoth roamed about in the forests where he and his companions lived.

Informazioni bibliografiche