We have seen that in the Carboniferous rocks there are two phases of sedimentation, the one marine, the other continental; corresponding with these there are two distinct faunal facies.
The divisions of the earth into faunal regions by Dr P. L.
But before an equal space of time had further elapsed, it had itself become a pest; the most recent information, however, is to the effect that its numbers are now on the decline, and that the disturbed faunal equilibrium is being readjusted.
The Hamilton fauna which followed represents the admixture of the resident Onondaga fauna with new types which are thought to have come from South America, showing that faunal connections for marine life had been made between the interior of the United States and the lands south of the Caribbean Sea, a connection of which, before this time, there was no evidence.
More than this, the Caspian was also, it is pretty certain, at the same epoch, and later, in direct communication with the Sea of Azov, no doubt by way of the Manych depression; for in the limans or lagoons of the Black Sea many faunal species exist which are not only identical with species that are found in the Caspian, but also many which, though not exactly identical, are closely allied.
Part many others belonging to the Canadian faunal area.
Most of the larger American mammals are not restricted to any one faunal zone.
Half of New Hampshire are many song birds belonging to the Alleghany faunal area; in the N.
Where two of the faunal realms meet there is usually, though not always, a mixing of faunas.
Throughout vegetation is scanty and faunal life poor in species, though in some respects certain of the species, e.g.