Elsewhere the plants generally indicate a higher horizon and are considered to correspond with the Rhaetic of Europe_ Jurassic beds are known only in the Cordillera itself, and the Cretaceous beds, which occur in the west of the country, are of freshwater origin.
This view is supported by Neumayr's comparison of Jurassic faunas throughout the world.
Geology.Many years ago it was pointed out by Elie de Beaumont and Dufrnoy that the Jurassic rocks of France form upon the map an incomplete figure of 8.
Jurassic Oeuonian Volcanic Rock, country was free from outbursts, except in the regions of the Alps and Pyrenees.
From the number of its cheek-teeth, the banded ant-eater has been regarded as related to some of the primitive Jurassic mammals; but this view is disputed by Mr Bensley, who regards this multiplicity of teeth as a degenerate feature.
On the other hand, it is noteworthy that this marsupial retains in its lower jaw the so-called mylo-hyoid groove, which is found in the aforesaid Jurassic mammals.
The Jurassic system is represented by two types.
In Victoria, Tasmania, northern New South Wales and Queensland, there are Jurassic terrestrial deposits, containing the coal seams of Victoria, of the Clarence basin of north-eastern New South Wales, and of the Ipswich series in Queensland; the same beds range far inland on the western slopes of the east Australian highlands in New South Wales and Queensland and they occur, with coal-seams, at Leigh's Creek, at the northern foot of the South Australian highlands.
These movements in the south-east formed the Great Valley of Victoria, which traverses nearly the whole of the state between the Victorian highlands to the north, and the Jurassic sandstones of the Otway Ranges and the hills of south Gippsland.
But the Blythesdale Braystone is a small local formation, unable to supply all the wells that have been sunk; and many of the wells derive their water from the Jurassic shales and mudstones.
Neumayr finds evidence of the existence of a continent between Africa and South America, which protruded into the central North Atlantic, in Jurassic times.
Once widely distributed in the Jurassic penod throughout the world, they are now dying out: the former is represented by the solitary maiden-hair tree of China and Japan; the latter by some ten species confined to the southern hemisphere, once perhaps their original home.
The Australian land-surface must be of great antiquity, possibly Jurassic, and its isolation scarcely less ancient.
During the Jurassic period the sea again invaded the region, both from the N.
During the Jurassic period the sea began again to invade Russia from S.E.
The limits of the Russian Jurassic system may be represented by a line drawn from the double valley of the Sukhona and Vytchegda to that of the upper Volga, and thence to Kieff, with a wide gulf penetrating towards the N.W.
To N.E., are filled up with Upper Jurassic deposits.
Geology unknown or unexplored shown thus Jurassic Trias & Permo-Trial r 'i ' Quaternary :.
The later beds of the island belong to the Jurassic, Cretaceous and Tertiary systems. At the western foot of the Ida massif calcareous beds with corals, brachiopods (Rhvnchonella inconstans, &c.) have been found, the fossils indicating the horizon of the Kimmeridge clay.
With the J urassic beds is associated an extensive series of eruptive rocks (gabbro, peridotite, serpentine, diorite, granite, &c.); they are chiefly of Jurassic age, but the eruptions may have continued into the Lower Cretaceous.
The structure is further complicated by a great thrust-plane which has brought the Jurassic and Lower Cretaceous beds upon the Upper Cretaceous and Eocene beds.
A remarkable &c, expedition by Baron Toll in 1892 through the regions watered by the Lena, resulted in the collection of material which Afghan- will greatly help to elucidate some of the problems which beset the geological history of the world, proving inter alia the primeval existence of a boreal zone of the Jurassic sea round the North Pole.
The greater part of western Asia, including the basin of the Obi, the drainage area of the Aral Sea, together with Afghanistan, Baluchistan, Persia and Arabia, was covered by the sea during the later stages of the Cretaceous period; but a considerable part 3f this region was probably dry land in Jurassic times.
Some of the deposits appear to be of Permian age, but others are probably Jurassic; and they are all included under the general name of the Angara series.
Excepting in the extreme north, where marine Jurassic and Cretaceous fossils have been found, there is no evidence that this part of Siberia has been beneath the sea since the early part of the Palaeozoic era.
In the same way the entire absence of any marine fossils in the peninsula of India, excepting near its borders, and the presence of the terrestrial and freshwater deposits of the Gondwana series, representing the whole of the geological scale from the top of the Carboniferous to the top of the Jurassic, show that this region also has been land since the Carboniferous period.
An interesting deposit of oolitic magnetic ore occurs in the Dogger (Inferior Oolite) of Rosedale Abbey, in Yorkshire; and a somewhat similar pisolitic ore, of Jurassic age, is known on the continent as chamoisite, having been named from Chamoison (or Chamoson) in the Valais, Switzerland.
In the Jurassic rocks are found Ephemeroptera and Odonata, as well as Hemiptera, referable to existing families, some representatives of which had already appeared in.
The oldest of the Jurassic ages - the Lias.
This order can be traced with certainty back to the early Jurassic epoch, while the Permian fossil Eugereon, and the living order - specially modified in many respects - of the Thysanoptera indicate steps by which the aberrant suctorial and piercing mouth of the Hemiptera may have been developed from the biting mouth of primitive Isopteroids, by the elongation of some parts and the suppression of others.
Abich (Sur la structure et la geologic du Daghestan, 1862), the successive folds of Jurassic limestones and slates, all nearly parallel to the Caucasus, which form lofty, narrow plateaus.
Ansariya, which presently springs up into a high chain of Jurassic limestone with basaltic intrusions, whose peaks rise to 10,000 ft.
Farther north, however, Jurassic beds are met with, but of very limited extent.
Along the west frontier there appear broad and strongly marked zones of Cretaceous limestone, alternating with Jurassic and Triassic, joined by a strip of Palaeozoic formations running from the north-west corner of Bosnia.
These do not occur on the west coast, but on the east coast the German expedition discovered marls and sandstones on Kuhn Island, resembling those of the Russian Jurassic, characterized by the presence of the genus Aucella, Olcostephanus Payeri, 0.
On the south coast of the same island are coarse-grained, brownish micaceous and light-coloured calcareous sandstone and marls, containing fossils, which render it probable that they are of the same age as the coal-bearing Jurassic rocks of Brora (Scotland) and the Middle Dogger of Yorkshire.
The Danish expeditions of 1899-1900 have added considerably to our knowledge of the Jurassic rocks of East Greenland.
Coal occurs in many Jurassic fresh-water;basins, namely, on the outskirts of the Altai, in south Yeniseisk, about Irkutsk, in the Nerchinsk district, at many places in the Maritime province, and on the island of Sakhalin.
Deslongchamps has described the tint of several Jurassic species.
The principal folding took place at the close of the Carboniferous period, and was contemporaneous with that of the old Hercynian chain of Belgium, &c. The Permian and later beds lie unconformably upon the denuded folds, and in the space between the Montagne Noire and the Cevennes proper the folded belt is buried beneath the horizontal Jurassic strata of the Causses.
During the Triassic and Jurassic periods even the basin of the Amazon appears to have been dry land.
Rising amid the ancient gneiss rocks of the St Gotthard, the Rhine finds its way down to the Lake of Constance between layers of Triassic and Jurassic formation; and between that lake and Basel it penetrates the chalk barrier of the Jura.
They are covered by marine Jurassic beds and they in turn by Cretaceous coal-bearing, terrestrial deposits, resembling those of New Zealand.
The Central Cordillera consists mainly of crystalline and volcanic rocks, on each side of which are aqueous, in great part Jurassic, strata thrown up almost vertically.
From the analogy of the neighbouring countries it is possible that some of the tuffs may be Jurassic, but the other deposits probably belong for the most part to the Cretaceous system.
The Cheilostomata are usually believed to have made their appearance in the Jurassic period.
Mesozoic rocks are represented by slates containing Ammoniles and Monotis, evidently of Triassic age, rocks containing Ammonites Bucklandi of Liassic age, a series of beds rich in plants of Jurassic age, and beds of Cretaceous age containing Trigonia and many other fossils.
The Jurassic and Cretaceous beds are also in part marine and in part terrestrial.
Geologically they are known to date back to the Oligocene period, and wings believed to be referable to them have been found in Liassic and Jurassic beds.
The Klippen are isolated hills, chiefly of Jurassic limestone, rising up in the midst of the later and softer deposits on the inner border of the sandstone zone.