236 Dr Mantell's Illustrations of the Connexion 



which are his contemporaries. The geologist on the other 

 hand, directs his views to the character and causes of the 

 changes, that have taken place throughout the organic and 

 inorganic kingdoms of nature ; from the period when " the 

 earth was without form and void,"" through the innumerable 

 ages chronicled by the relics of the races of animals and 

 plants which have successively appeared, and flourished 

 awhile, and become extinct : his investigations also embrace 

 the consideration of the physical revolutions which have swept 

 over the earth's surface during the human epoch, and of those 

 that are still in progress. 



In the ancient sedimentary rocks, the remains of the ani- 

 mals and plants which inhabited the land, the rivers, and 

 the seas, when those strata were deposited, occur in such 

 abundance and variety, that the naturalist can readily deter- 

 mine the characters of the terrestrial and marine faunas and 

 floras which prevailed in those remote eras. The elementary 

 principles of geology are now so generally disseminated, that 

 I take it for granted every intelligent person is aware that 

 all the rocks and strata composing the dry land were origi- 

 nally in a softened or fluid state, either from the efi^ects of 

 water or from exposure to a high temperature ; — that the 

 strata are accumulations of mud, sand, or other detritus, the 

 sedimentary deposits of streams, rivers, and seas, combined 

 with the durable remains of animals and plants which lived 

 either on the land or in the water ; — that these beds of or- 

 ganic and inorganic materials have been consolidated by 

 chemical and mechanical agency, and subsequently been 

 elevated from beneath the waters, at various periods, by 

 those physical forces which are constantly in action, in the 

 profound depths of the earth, and of which the earthquake 

 and the volcano are the paroxysmal effects ; — and that such 

 transmutations of the sea and of the land are perpetually 

 taking place. 



Throughout the entire series of the secondary and tertiary 

 formations, though the most recent of the latter contain relics 

 of species now existing, no traces of the human race have 

 been discovered. It is only in the deltas, estuaries, and allu- 

 vial and turbary deposits, of comparatively modern times, — 



