The termination of the carboniferous formation is marked by symptoms of volcanic violence, which some geologists have considered to denote the close of one system of things and the beginning of another. Coal beds generally lie in basins, as if following the curve of the bottom of seas. But there is no such basin which is not broken up into pieces, some of which have been tossed up on edge, others allowed to sink, causing the ends of strata to be in some instances many yards, and in a few several hundred feet, removed from the corresponding ends of neighbouring fragments. These are held to be results of volcanic movements below, the operation of which is further seen in numerous upbursts and intrusions of volcanic rock (trap). That these disturbances took place about the close of the formation, and not later, is shewn in the fact of the next higher group of strata being comparatively undisturbed. Other symptoms of this time of violence are seen in the beds of conglomerate which occur amongst the first strata above the coal. These, as usual, consist of fragments of the elder rocks, more or less worn from being tumbled about in agitated water, and laid down in a mud paste, afterwards hardened. Volcanic disturbances break up the rocks; the pieces are worn in seas; and a deposit of conglomerate is the consequence. Of porphyry, there are some such pieces in the conglomerate of Devonshire, three or four tons in weight. It is to be admitted for strict truth that, in some parts of Europe, the carboniferous formation is followed by superior deposits, without the appearance of such disturbances between their respective periods; but apparently this case belongs to the class of exceptions already noticed. {93} That disturbance was general, is supported by the further and important fact of the destruction of many forms of organic being previously flourishing, particularly of the vegetable kingdom. ERA OF THE NEW RED SANDSTONE. TERRESTRIAL ZOOLOGY COMMENCES WITH REPTILES. FIRST TRACES OF BIRDS. THE next volume of the rock series refers to an era distinguished by an event of no less importance than the commencement of land animals. The _New Red Sandstone System_ is subdivided into groups, some of which are wanting in some places; they are pretty fully developed in the north of England, in the following ascending order:—1. Lower red sandstone; 2. Magnesian limestone; 3. Red and white sandstones and conglomerate; 4. Variegated marls. Between the third and fourth there is, in Germany, another group, called the Muschelkalk, a word expressing a limestone full of shells.