This radical and world-wide change in climate, therefore, demands ample consideration when seeking a true induction as to the past of our globe. That it was no gradual or secular affair, but that the climate "became =suddenly= extreme as of a single winter's night," the Siberian "mummies" are unanswerable arguments. =That it occurred within the human epoch= all are now agreed. FOOTNOTES: [68] "The Glacial Nightmare and the Flood," pp. 426-479. [69] "Manual," pp. 484, 524-5. [70] Op. cit., pp. 434-5. [71] Id., p. 45. [72] "Island Life," pp. 182, 195-6; "Nightmare," pp. 455-6. [73] "Historical Geology," p. 76. [74] "Manual," p. 997. [75] p. 225, Edition of 1875. [76] See Dana's "Manual," pp. 945, 977; also "The Glacial Nightmare," pp. 45-2, 511, etc. [77] "Great Ice Age," p. 129; "Nightmare," p. 473. [78] See _Nature_ April 11, 1901, p. 560. CHAPTER XI DEGENERATION There is another great general fact about the fossil world which seems to be a natural corollary from the one already given about climate. It is this: =The fossils, regarded as a whole, invariably supply us with types larger of their kind and better developed in every way than their nearest modern representatives, whether of plants or animals.= This fact also is so well known that it needs no proof. Through the whole range of geological literature I do not know of a word of dissent from this general fact by any writer whatever. Proof therefore is not necessary, though a brief review of a little of the evidence may refresh our memories. To begin with the Cambrian, Dana says: "The Pteropods, among Mollusks, were much larger than the modern species of the tribe. The Trilobites even of the Lower Cambrian comprise species as large as living Crustaceans. The Ostrapods are generally larger than those of recent times."[79] Again, in speaking of the general character of the Cambrian fossils, he says: "The types of the early Cambrian are mostly identical with those now represented in existing seas, and although inferior in general as to grade [in the "Phylogenic series"], they bear no marks of imperfect or stunted growth from unfit or foul surroundings." (p. 485.) The well known Mollusk, _Maclurea magna_, which is so enormously abundant in the Silurian, is often eight inches in diameter, and the astounding Cephalopod genus, _Endoceras_, consisting of twenty species, found only in two divisions of the Lower Silurian, has left shells over a foot in diameter, and ten or twelve feet long! Of the fishes of the Devonian we have, among other remarks of a similar character, the following: