Not improbably this country was either "Gondwana-land," connecting Mesozoic India with Africa, or perhaps Africa itself.
And when we know that the Chrysomelidae and Buprestidae also lived in Triassic, and the Carabidae, Elateridae, Cerambycidae and Scarabaeidae, in Liassic times, we cannot doubt that the great majority of our existing families had already been differentiated at the beginning of the Mesozoic epoch.
South and west of the Fossa Magna the beds are thrown into folds which run approximately parallel to the general direction of the coast, and two zones may be recognizedan outer, consisting of Palaeozoic and Mesozoic beds, and an inner, consisting of Archaean and Palaeozoic rocks, with granitic intrusions.
In the eastern region this was the last folding which has affected the country, and the Mesozoic and Tertiary beds are almost undisturbed.
In the western region, on the other hand, all the Mesozoic beds are involved in a later system of folds; but here also the Tertiary beds lie nearly horizontal.
There were, therefore, two principal epochs of folding in the island, one at the close of the Palaeozoic era which affected the whole of the island, and one at the close of the Mesozoic which was felt only in the western region.
In the western region all the Mesozoic systems, including the Trias, are well developed.
The Mesozoic beds are limited in extent, the most extensive areas lying around the Gulf of Orosei on the east and west of Sassari in the north.
As far west, therefore, as the Cordillera, there is no evidence that any part of the region was ever beneath the sea in Mesozoic times, and the plant-remains indicate a land connexion with Africa.
Within the northern circle of the 8 lie the Mesozoic and Tertiary beds of the Paris basin, dipping inwards; within the southern circle lie the ancient rocks of the Central Plateau, from which the later beds dip outwards.
Outside the southern circle lie on the west the Mesozoic and Tertiary beds of the basin of the Garonne, with the Pyrenees beyond, and on the east the Mesozoic and Tertiary beds of the valley of the Rhne, with the Alps beyond.
In France, as in Great Britain, volcanic eruptions occurred during several of the Palaeozoic periods, but during the Mesozoic era the // /
Under the heading of Multituberculata will be found a brief account of certain extinct mammals from the Mesozoic formations of Europe and North America which have been regarded as more or less nearly related to the monotremes.
The latter has indeed been regarded as the direct descendant of these Mesozoic forms; but as already stated, in the opinion of Mr B.
Osborn, "Mesozoic Mammalia," Journ.
The Mesozoic begins with a Triassic land period in the mainland of Australia; while the islands of the Australasian festoon contain the Triassic marine limestones, which fringe the whole of the Pacific. The Triassic beds are best known in New South Wales, where round Sydney they include a series of sandstones and shales.
Neumayr, while they regard the basin of the Pacific as of great antiquity, believe the Atlantic to date only from the Mesozoic age.
Both were in turn replaced by the Lower Mesozoic flora, which again is thought to have had its birth in the hypothetical Gondwana land, and in which Gymnosperms played the leading part formerly taken by vascular Cryptogams. The abundance of Cycadean plants is one of its most striking features.
Though now on the way to extinction, Cycadeae are still widely represented in the southern hemisphere by genera which, however, have no counterpart in the Mesozoic era.
The later period of the Mesozoic era saw the almost sudden advent of a fully developed angiospermous vegetation which rapidly occupied the earths surface, and which it is not easy to link on with any that preceded it.
It confirms the general belief on geological grounds that this was the seat of their development at the close of the Mesozoic era.
Over the greater part of the Cambrian country the strata are still nearly as flat as when they were first laid down, and the deposits, even of the Cambrian period, are as soft as those of the Mesozoic and Tertiary formations in England.
At the beginning of the Mesozoic era the whole country became land, bearing upon its surface the salt lakes in which the Trias was laid down.
In the south, in Syria, Arabia and the peninsula of India, none but the oldest rocks are folded, and the Upper Palaeozoic, the Mesozoic and the Tertiary beds lie almost horizontally upon them.
North of this lies a broad belt in which the Mesozoic deposits and even the lower divisions of the Tertiary system are thrown into folds which extend in a series of arcs from west to east and now form the principal mountain ranges of central Asia.
North of the folded belt, and including Emery the greater part of Siberia, Mongolia and northern China, lies another area which is, in general, free from any important folding of Mesozoic or Tertiary age.
In the extreme north, in the Verkhoyansk range and in the mountains of the Taimyr peninsula, there are indications of another zone of folding of Mesozoic or later date, but our information concerning these ranges is very scanty.
It is interesting to observe, as will be shown later, that during the Mesozoic era there was a land-mass in the north of Asia and another in the south, and between them lay the sea in which ordinary marine sediments were deposited.
Between these ancient land masses lies an area in which marine deposits of Mesozoic age are well developed and which was evidently beneath the sea during the greater part of the Mesozoic era.
Here again there are no marine beds of Mesozoic or Tertiary age, while plant-bearing deposits belonging to the Angara series are known.
Southern China is very different in structure, consisting largely of folded mountain chains, but the geological succession is very similar, and excepting near the Tibetan and Burmese borders, there are no marine deposits of Mesozoic or Tertiary age.
The Triassic deposits of the Verkhoyansk Range show that this land did not extend to the Bering Sea; while the marine Mesozoic deposits of Japan on the east, the western Tian-shan on the west and Tibet on the south give us some idea of its limits in other directions.
Between India and China there is a broad belt in which marine deposits of Mesozoic and Tertiary age are well developed.
Marine Tertiary beds occur in Burma; in the Himalayas and in south Tibet there is a nearly complete series of marine deposits from the Carboniferous to the Eocene; in Afghanistan the Mesozoic beds are in part marine and in part fluviatile.
The Silurian mica-schists of Bergen in Norway are fossiliferous; in the Alps it is believed that even Mesozoic rocks pass laterally into mica-schists and talc-schists.
With the dawn of the Mesozoic epoch we reach Hexapods that can be unhesitatingly referred to existing orders.
None of the groups of existing Endopterygota have been traced with certainty farther back than the Mesozoic epoch, and all the numerous Palaeozoic insect-fossils seem to belong to forms that possessed only imperfect metamorphosis.
As shown by the number and variety of species, the Orthoptera are the most dominant order of this group. Eminently terrestrial in habit, the differentiation of their fore-wings and hindwings can be traced from Carboniferous, isopteroid ancestors through intermediate Mesozoic forms. The Plecoptera resemble the Ephemeroptera and Odonata in the aquatic habits of their larvae, and by the occasional presence of tufted thoracic gills in the imago exhibit an aquatic character unknown in any other winged insects.
The occurrence of weevils - among the most specialized of the Coleoptera - in Triassic rocks shows us that this great order of metabolous insects had become differentiated into its leading families at the dawn of the Mesozoic era, and that we must go far back into the Palaeozoic for the origin of the Endopterygota.
The only Mesozoic system which is represented in Brazil by marine beds is the Cretaceous, and the marine facies, is restricted to the coasts and the basin of the Amazon.
The hilly regions of Transylvania and of the northern part of Hungary consist of Palaeozoic and Mesozoic rocks and are closely connected, both in structure and origin, with the Carpathian chain.
The second element in the composition of the island consists of Mesozoic beds, which occur in a broken band along most of the south-western coast.
Geology.'--The Eastern Cordillera., which, however, is but little known, appears to consist, as in Bolivia, chiefly of Palaeozoic rocks; the western ranges of the Andes are formed of Mesozoic beds, together with recent volcanic lavas and ashes; and the lower hills near the coast are composed of granite, syenite and other crystalline rocks, sometimes accompanied by limestones and sandstones, which are probably of Lower Cretaceous age, and often covered by marine Tertiary deposits.
The constitution of the Mesozoic band varies.
Farther north, in the department of Ancachs, the Mesozoic belt is composed chiefly of sandstones and shales, and the limestones which form so prominent a feature above Lirna seem to have disappeared.
In the Cordillera Nevada the Mesozoic rocks which form the chain are often covered by masses of modern volcanic rock.
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.
During the whole of the Mesozoic era Japan appears to have lain on or near the margin of the Asiatic continent, and the marine deposits are confined for the most part to the eastern side of the islands.
This foundation consists of Archean, Palaeozoic and Mesozoic beds folded together, the direction of the folds being N.
In the outer portion of the zone the Permian and Mesozoic beds are crushed and folded against the core of ancient rocks; in the inner portion of the zone they rest upon the old foundation with but little subsequent disturbance.
In the eastern Carpathians also, the Permian and Mesozoic beds are not much folded except near the outer margin of the zone.
In these respects they contrast with the great oceans which owe their origin to the most extensive and the profoundest depressions of the crust, date back at least to Mesozoic times, and have perhaps remained permanently in their present position from still remoter ages.
Mesozoic coals are more abundant in the southern hemisphere, while Tertiary coals seem to be tolerably uniformly distributed irrespective of latitude.
New Zealand includes representatives of all the three Mesozoic systems. The Hokanui group comprises the Triassic Wairoa .and Otapira beds, and the Jurassic Mataura beds.
Along the northern margin lies the intensely folded belt which constitutes the coalfield of Namur, and, beneath the overlying Mesozoic beds, is continued to the Boulonnais, Dover and beyond.
Unlike most Irish counties, Antrim owes its principal features to rocks of Mesozoic and Cainozoic age.
Successive observers in Italy, notably Fracastoro (1483-1553), Fabio Colonna (1567-1640 or 1650) and Nicolaus Steno (1638 - c. 1687), a Danish anatomist, professor in Padua, advanced the still embryonic science and set forth the principle of comparison of fossil with living forms. Near the end of the 17th century Martin Lister (1638-1712), examining the Mesozoic shell types of England, recognized the great similarity as well as the differences between these and modern species, and insisted on the need of close comparison of fossil and living shells, yet he clung to the old view that fossils were sports of nature.
Observing for himself (1794-1800) the stratigraphic value of fossils, he began to distinguish the great Mesozoic formations of England (1801).
His contributions on the Mesozoic reptiles of Great Britain culminated in his complete rearrangement and classification of this group, one of his greatest services to palaeontology.
On the other hand, limestone and sandstone, especially of the Mesozoic strata, are strikingly deficient.