However great its physical advances may be, Geology remains imperfect till it is wedded with Palaeontology,[2] a study which essentially belongs to the vast complex of the Biological Sciences, but at the same time has its strictly geological side.

Dealing, as it does, wholly with the consideration of such living beings as do not belong exclusively to the present order of things, Palaeontology is, in reality, a branch of Natural History, and may be regarded as substantially the Zoology and Botany of the past.

It is the ancient life-history of the earth, as revealed to us by the labours of palaeontologists, with which we have mainly to do here; but before entering upon this, there are some general questions, affecting Geology and Palaeontology alike, which may be very briefly discussed.
[Footnote 1: Gr.

_ge_, the earth; _logos_, a discourse.] [Footnote 2: Gr.

_palaios_, ancient; _onta_, beings; _logos_, discourse.] The working geologist, dealing in the main with purely physical problems, has for his object to determine the material structure of the earth, and to investigate, as far as may be, the long chain of causes of which that structure is the ultimate result.