Cuvier's great work, entitled _Ossemens Fossiles_, will long remain an imperishable monument of the genius and industry of the greatest pioneer in this region of investigation. This work proved beyond a doubt to his astonished contemporaries the great antiquity of the tribes of animals now living on the surface of the earth. It proved more than that, however; for it showed the existence of a great philosophy in Nature which linked the past with the present in a scheme that pointed to a continuity of life during untold previous ages. All this was directly at variance with the prevalent ideas of his time, and consequently his views were regarded by many with alarm, and he received a good deal of abuse--a fate which many other original thinkers before him have shared. It is somewhat difficult for people living now, and accustomed to modern teaching, to realise how novel were the conclusions announced by Cuvier. In his _Discourse on the Revolutions of the Surface of the Globe_, translated into most European languages under the title _Theory of the Earth_, he lays down, among others, the two following propositions:-- 1. That all organised existences were not created at the same time; but at different times, probably very remote from each other--vegetables before animals, mollusca and fishes before reptiles, and the latter before mammals. 2. That fossil remains in the more recent strata are those which approach nearest to the present type of corresponding living species. Teaching such as this gave a new impetus to the study of organic remains, and Palæontology, as a science, began with Cuvier. CHAPTER I. HOW EXTINCT MONSTERS ARE PRESERVED. "Geology, beyond almost every other science, offers fields of research adapted to all capacities and to every condition and circumstance of life in which we may be placed. For while some of its phenomena require the highest intellectual powers, and the greatest attainments in abstract science for their successful investigation, many of its problems may be solved by the most ordinary intellect, and facts replete with the deepest interest may be gleaned by the most casual observer."--Mantell.