16 INTRODUCTION. 



These two are embraced in Mr Lyell's Recent Period, and 

 here are found to exist the remains of those large animals, 

 the Mastodon, Hippopotamus, Megatherium, Rhinoceros, &c. 

 &c. To this Recent Period, belong the causes which 

 are now so evidently in action, and with which we are fami- 

 liar, such as the formation of coral reefs and islands, deltas, 

 travertins, active volcanoes, &c. 



Viewing these changes, the facts of which have been 

 established by the united exertions of geologists, within 

 a comparatively short period, we reflect with intense in- 

 terest on the disappearance from our planet of an im- 

 mense number of species, numerous genera, and even 

 some families ! 



The causes of the vast changes which it is evident to 

 our senses, have taken place, are among the most inter- 

 esting which have engaged the attention of mankind. 

 Theories of all kinds have been promulgated, and little good 

 has arisen from them, except that of the gradual develop- 

 ment of facts, the accumulation of which has added to 

 our stock of knowledge. It is said to be Fuchsel (a 

 German geologist) who first asserted that the causes 

 now in operation were sufficient to produce the changes 

 observed in our strata. " Similar changes may now take 

 place ; for the earth has always presented phenomena similar 

 to those of the present day"* Such is the remarkable 

 language of the author, published about seventy years 

 since. Very recently, the theory of actual causes has 

 been considered in England, by some of her ablest geolo- 

 gists, as sufficient to satisfy the attentive observer. Mr 

 Lyell may now be considered as tne leader of this theory, 

 and the mass of facts brought together in his admirable 

 work, would seem to be enough to satisfy the most scep- 

 tical. 



The rapid change which is now going on in the 



* De la Beche's Geol. Man., p. 382, first English edition. 



