Species of the Secondary and Tertiary Formations ? 259 



which we possess certain data, prove that there is nothing 

 in common between the two creations. The difference be- 

 tween the races of the two worlds, is so much the greater as 

 they belong to the most ancient ages ; but, independently of 

 this circumstance, which always leads to the same result, 

 there is nothing identical between the generations which be- 

 long to epochs so diverse. Geological facts support, with all 

 their weight, this remarkable circumstance, which an enlight- 

 ened and attentive comparison of the species of the two crea- 

 tions confirms more and more every day. 



The races belonging to the ancient creations have, there- 

 fore, no longer any representatives on the earth, but, what is 

 no less remarkable, it is the same with a portion of the ac- 

 tual races. Many species of the creation to which we be- 

 long have perished ; some of them at a period of a cataclysm 

 which has desolated a great part of the earth's surface, and 

 others in recent times. 



These facts, singular and extraordinary as they may ap- 

 pear at first sight, are yet true in regard to a certain num- 

 ber of the species of different epochs, though they belong to 

 our period. When we reflect on the causes which have dcr 

 stroyed many races of our creation, we are soon convinced 

 that they are very simple, and that the fact of their destruction 

 comes within the ordinary course of things. It is enough to 

 produce it, that the number of deaths should be proportionally 

 greater than that of births ; the more the former exceeds the 

 latter, the more certain and rapid is the extinction of every 

 race. — (^Marcel de Serres, Bib. Univ.^ p. 241, No. 7, Aout 

 1846.) 



On the Destruction and partial Beproduction of Forests in 

 British North America. By John William Dawson, 

 Esq. of Pictou. Communicated by the Author. 



The changes produced by the agency of civilized man, in 

 the condition of the earth's surface, and the numbers and 

 distribution of its living inhabitants, though not of great im- 

 portance when compared with those which result from the 

 unceasing operation of natural causes, are interesting to the 



