It is my object, in the following work, to travel over ground which has as yet been little explored and to make my reader acquainted with a species of Remains, which, though absolutely necessary for understanding the history of the globe, have been hitherto almost uniformly neglected.

It is my object, in the following work, to travel over ground which has as yet been little explored and to make my reader acquainted with a species of Remains, which, though absolutely necessary for understanding the history of the globe, have been hitherto almost uniformly neglected.

It has been long considered possible to explain the more ancient revolutions on... the Earth surface by means of these still existing causes; in the same manner as it is found easy to explain past events in political history, by an acquaintance with the passions and intrigues of the present day. But we shall presently see that unfortunately this is not the case in physical history:-the thread of operation is here broken, the march of nature is changed, and none of the agents that she now employs were sufficient for the production of her ancient works.

My object will be, first, to show by what connections the history of the fossil bones of land animals is linked to the theory of the earth and why they have a particular importance in this respect.

Secondly, the nature of the revolutions which have altered the surface of the earth must have had a more decisive effect on the terrestrial quadrupeds than on the marine animals.

At the sight of a single bone, of a single piece of bone, I recognize and reconstruct the portion of the whole from which it would have been taken. The whole being to which this fragment belonged appears in my mind's eye.

But the revolutions and changes which are responsible for the present state of the earth are not limited to the upsetting of the ancient strata and to the ebbing of the sea after the formations of new layers.