In the latter place they contain workable coal-seams. The Carboniferous Limestone often contains black flint (chert), and at some horizons conglomerates occur, the pebbles being derived from the unconformable ridges of the " Caledonian " land.
She is a thorough woman, but with none of the pettinesses, subterfuges, and mental reservations of her sex; she loves wide vistas and boundless horizons and instinctively seeks them out; she is concerned for universal happiness and takes thought for the improvement of mankind - thelastinfirmity and most innocent mania of generous souls.
There is considerable difference of opinion as to the chronology of the succeeding beds, and the boundary between the Cretaceous and Tertiary systems is drawn at various horizons by different observers.
The igneous rocks occur at several geological horizons, but the great volcanic eruptions did not begin until the Tertiary period.
Hatcher, demonstrate the Pleistocene nature of the deposits, by which is not necessarily meant older Quaternary, for their horizons have not been differentiated and correlated in South America.
Phosphatic nodules and concretions, with phosphatized fossils and their casts, occur at various geological horizons in Great Britain.
Bach's sonatas; then the medium itself began to suggest wider horizons and new possibilities of treatment; his position at Eisenstadt enabled him to experiment without reserve; his genius, essentially symphonic in character, found its true outlet in the opportunities of pure musical structure.
Beginning in 1793 he boldly advocated evolution, and further elaborated five great principles--namely, the method of comparison of extinct and existing forms, the broad sequence of formations and succession of epochs, the correlation of geological horizons by means of fossils, the climatic or environmental changes as influencing the development of species, the inheritance of the bodily modifications caused by change of habit and habitat.
Deperet points also that we owe to Cuvier the first clear expression of the idea of the increasing organic perfection of all forms of life from the lower to the higher horizons, and that, while he believed that extinctions were due to sudden revolutions on the surface of the earth, he also set forth the pregnant ideas that the renewals of animal life were by migration from other regions unknown, and that these migrations were favoured by alternate elevations and depressions which formed various land routes between great continents and islands.
It is certainly a very striking fact that wherever we have been able to trace genetic series, either of invertebrates or vertebrates, in closely sequent geological horizons, or life zones, we find strong proof of evolution through extremely gradual mutation simultaneously affecting many parts of each organism, as set forth above.
This is not due to environmental conditions solely, because senescent branches of normal progressive groups are found in all geologic horizons, beginning, for gastropods, in the Lower Cambrian.
The zinc and lead of the Joplin district of Missouri are in the limestone of this system, and the corresponding limestone in some parts of Colorado, as at Leadville, is one of the horizons of rich ore.
The geologic record is, as perhaps is to be expected, exceedingly poor, except as regards the calcareous Siphonales, which are well represented at various horizons, from the Silurian to the Tertiary; even the Diatomaceae, which are found in great quantities in the Tertiary deposits, do not occur at all earlier than the chalk.
The Middle Oolite consists mostly of sandstones with bands of shale and limestones, and includes fossils which indicate the English horizons from the Kellaways Rock up to the Coral Rag.
The Ionian islands consist almost entirely of Cretaceous and Tertiary beds, but in Corfu Jurassic deposits belonging to various horizons have also been found.
The plant beds occur at several horizons, and among the remains which have been found in them are several forms which occur also in the Gondwana beds of India.
Undoubted Jurassic fossils, belonging to several horizons, have been described from west Borneo and Sarawak.
The Russian Altai is composed mainly of mica and chlorite schists and slates, together with beds of limestone, and in the higher horizons Devonian and Carboniferous fossils occur in many places.
Many British species and associations of genera and species, occurring on corresponding horizons to those on which they are found in Britain, have been met with in the graptolite-bearing Lower Palaeozoic formations of other parts of Europe, in America, Australia, New Zealand :and elsewhere.
Other characters, however, prove that the Cordaiteae were remote from that family, and the name Araucarioxylon is best Limited to wood from later horizons, where a near relationship to Araucarieae is more probable.'
Any detailed account of the horizons of Carboniferous plants would carry us much too far.
Fossil wood, described under the name Cupressinoxylon, has been recorded from several Mesozoic horizons in Europe and elsewhere, but this term has been employed in a wide sense as a designation for a type of structure met with not only in the Cupressineae, but in members of other families of Coniferae.
Not only could he no longer think the thoughts that had first come to him as he lay gazing at the sky on the field of Austerlitz and had later enlarged upon with Pierre, and which had filled his solitude at Bogucharovo and then in Switzerland and Rome, but he even dreaded to recall them and the bright and boundless horizons they had revealed.
Deshayes (1830) worked out the percentages of recent fossils found at several horizons in those strata, and upon this Sir C. Lyell (1852) founded the main periods, viz.
Insigne, has scalariform tracheides, and is traversed by regular medullary rays, but in the forms from later ' horizons the tracheides are reticulately pitted, and the rays are for the most part replaced by a network of xylem-parenchyma.