085  086  087  088  089  090  091

 111  112  113  114  115  116  117

1. Effect of Solar Heat on the Earth  145
2. Climate  146
3. Temperature of the Interior of the Earth  147
4. Heat of the Planetary Spaces 148

[517] So long as the organic fossils which were found in the strata of the earth were the remains of marine animals, it was very difficult for geoloists to be assured that the animals were such as did not exist in any part or clime of the existing ocean. But when large land and river animals were discovered, different from any known species, the persuasion that they were of extinct races was forced upon the naturalist. Yet this opinion was not taken up slightly, nor acquiesced in without many struggles.

Bones supposed to belong to fossil elephants, were some of the first with regard to which this conclusion was established. Such remains occur in vast numbers in the soil and gravel of almost every part of the world; especially in Siberia, where they are called the bones of the mammoth.... In 1796, Cuvier ... stated the results of his researches. "With regard to what have been called the fossil remains of elephants, from Tentzelius to Pallas, I believe that I am in the condition to prove, that they belong to animals which were very clearly different in species from our existing elephants, although they resembled them sufficiently to be considered as belonging to the same genera."

[518] We have here, then, the starting-point of those researches concerning extinct animals... Cuvier could hardly have anticipated the vast storehouse of materials which lay under his feet, ready to supply him occupation of the most intense interest.

[525] Among the events belonging to the diffusion of sound geological views in this country, we may notice the publiction of a little volume entitled The Geology of England and Wales, by Mr. Conybeare and Mr. Phillips, in 1821; an event far more important than, from the modest form and character of the work, it might at first sight appear. By describing in detail the geological structure and circumstances of England (at least as far downward as the coal), it enabled a very wide class of readers to understand and verify the classifications which geology had then very recently established.

[529] Those descriptive names only have been really useful in geology which had been used withoug any scrupulous regard to the appropriateness of the description. The Green Sand may be white, brown, or red; the Mountain Limestone may occur only in valleys; the Oolite may have no roe-like structure; and yet these may be excellent geological names, if they be applied to formations geologically identical with those which the phrases originally designated. The signification may assist the memory, but must not be allowed to subjugate the faculty of natural classification.

[537] The extension of geological surveys, the construction of geological maps, and the determination of geological equivalents... have been carried on ... with enlarged activity, range and means. It is estimated that one-third of the land of each hemisphere has been geologically explored; and that thus Descriptive Geology has now been prosecuted so far, that it is not likely that even the extensioin of it to the whole globe would give any material novelty of aspect.