THE SURFACE OF THE GLOBE. 133 



requisite to discover the cause of these events, an undertaking of a 

 very different nature. 



I repeat, we see very clearly what is passing on the surface of the 

 continents in their present state ; we have very fairly ascertained the 

 unifoim march and regular succession of the primitive formations, but 

 the study of secondary formations has scarcely yet commenced ; that 

 wonderful series of unknown zoophytes, and marine moUusca, followed 

 by reptiles and fresh-water fish equally unknown, and these in their 

 turn replaced by zoophytes and mollusca more akin to those of the 

 present day ; those land animals and mollusca, and other fresh- water 

 animals, also unknown, which next occupy the places, to be again dis- 

 placed, but by mollusca and other animals similar to those of our own 

 seas ; the relations of these various beings with the plants, whose re- 

 mains accompany theirs 3 the relations of these two kingdoms with the 

 mineral layers which contain them ; the more or less their uniformity 

 with one another in different basins ; all these are a series of pheno- 

 mena which appears to me to call imperiously for the profound atten- 

 tion of philosophers. 



Made interesting by the variety of the productions of the partial or 

 universal revolutions of this epoch, and by the abundance of the va- 

 rious species which alternately figure on the stage, this study is divested 

 of the dryness of that of the primordial formations, and does not, like 

 it, plunge itself into hypotheses. The facts are so close, so curious, 

 and so evident, that they suffice, in a measure, for the most ardent 

 imagination ; and the conclusions which they arrive at from time to 

 time, however scrupulous the observer may be, not having anything 

 indefinite, at the same time have nothing arbitrary. Finallj, it is in 

 the events which are nearer to our own times that we can hope to find 

 any traces of the more ancient events and their causes, if it be indeed 

 allowed, after so many trials, to flatter ourselves with such a hope. 



These ideas have beset, I may say, have tormented me, whilst I have 

 been engaged in making researches amongst fossil bones, the results of 

 which I have lately made public ; researches which only comprise so 

 small a portion of these phenomena of the last age but one of the earth, 

 and which, notwithstanding, are united to all the others, in an intimate 

 manner. It was nearly impossible that the desire of studying the ge- 

 nerality of these phenomena should not arise, at least, in a limited 

 space around us. My excellent friend, M. Brongniart, in whom other 

 studies had excited similar desires, "desired me to associate with him, 

 and thus we have laid the first foundations of our researches in the 

 vicinity of Paris ; but this work, although it bears my name, is nearly 



