found fossil in British Strata. 381 



we have as yet with comparative geology. But a small portion of 

 the earth's surface has as yet been examined with that minuteness 

 which the palasontologist should require before he infers sweeping 

 conclusions from negative facts. As well might the zoologist or bo- 

 tanist, having thoroughly explored one province, or even a con- 

 nected group of provinces of distribution, draw from his researches 

 general conclusions respecting the presence or absence of like beings 

 with those which he has examined on other parts of the earth's sur- 

 face before they had been explored by competent persons. If many 

 distant points be thoroughly examined, we may hope to come to 

 tolerably correct inferences respecting the phenomena of life in the 

 interspaces, and this is as true in time- investigations as in space-in- 

 vestigations ; but in geology, until lately, our knowlege of the fossil 

 faunas and floras of distant regions has been, and indeed is still, ex- 

 tremely limited ; for the parts of the world best examined, viz., 

 Europe and North America, have evidently, in a natural history 

 point of view, been portions of one province only ; vast, no doubt, 

 but not vaster than some existing provinces of distribution recognised 

 by those naturalists who have studied that important subject. ° Yet, 

 this not having been borne in mind, speculations, presented as infer- 

 ences from extensive series of facts, respecting the universal diffusion 

 of species during the older epochs of the world's history; the evidence 

 they afforded of a universal climate ; the progression of organisation 

 in time ; the development of higher forms from lower ; the absence 

 of great classes of organised beings ; and the causes of that absence 

 dependent on the existence of pecuHar atmospheric or terrestrial con- 

 ditions, have been rife in geology ; and though probably partially 

 true, yet, as the logical process by which many of them were ar- 

 rived at is not quite clear, whilst the premises were often evidently 

 insuflicient, have led many able men, unacquainted with the certain- 

 ties of our science, too hastily to regard geology as in great part a 

 philosophical romance. 



When we consider the enormous lapse of time which has rolled 

 away since the earlier formations were deposited ; the changes which 

 have taken place on the earth's surface during the interval ; the 

 wear and tear which the hardest rocks must have undergone during 

 their upheavals and depressions ; the little that is preserved to us of 

 sea-beds which have been extensively exposed during comparatively 

 recent times, — the wonder is, not that we can find no traces of tho 

 former existence of numerous tribes of creatures, members of which 

 now live upon our earth and its seas ; but that so many types of 

 forms, simulating existing organisms, should be preserved at all as 

 evidences of the most ancient past. It is from positive, and not from 

 negative evidences, then, that the palaeontologist should draw his con- 

 clusions, unless when well-established laws, arrived at by naturalists 

 from the careful study of the full and unmutilated chapter of tho 

 VOL. XLV. NO. XC. — OCTOBER 1848. 2 C 



