(Harper's geoscience series) Rev. & expanded edition of Interpretation of geologic maps and aerial photographs.

The preponderance of land in the northern hemisphere denotes the greater intensity there of the causes of elevation at a remote geologic epoch: that is all that one can say about it: but whence that greater intensity?

Long enough ago, again, to allow that lowland to be sawn out into hills and valleys, ridges and gulleys, which are due to the action of Colonel George Greenwood's geologic panacea, 'Rain and Rivers,' and to nothing else.

The exceedingly rich bird fauna of South America contains many species which seem to be survivals from a very remote geologic past, whose kinsfolk have perished under the changed conditions of recent ages; and in the case of many, like the hoatzin and screamer, their like is not known elsewhere.

For it is not a studied knowledge; it resembles that slow geologic uncovering before which not even the deep buried bones of the prehistoric saurian remain finally hidden.