Observations Concerning Fossil Organic Remains. 103 



distances, from each other, placed between the same rocks 

 a and y are formed at the same epoch, because they contam 

 the same organic remains, and possess the same composi- 

 tion ; it is not on that account, equally probable that the 

 epochs of their formation are very distant from each other, 

 when the fossils ate dissimilar. We conceive that in the 

 same zone, in a country of small extent that the generations 

 of animals have succeeded each other, and characterized 

 as it vi^ere, by peculiar types the epochs of their formations ; 

 but beings of various forms at great horizontal distances, 

 may have occupied at the same time, in different climates, 

 the surface of the globe, or the basin of the* sea. We may 

 observe farther, that the position of ,8 between a and y proves 

 that it is anterior to the formation y and posterior to that of 

 a; but there is nothing which, enables us to measure the 

 interval of time which elapsed between the deposition of 

 the strata; and the different isolated deposits of /3 may not 

 be simultaneous." 



I have taken my last remarks from the essay of the cele- 

 brated M. de Humboldt upon the superposition of rocks, be- 

 cause they appeared to me to be connected with those ob- 

 servations which I have taken the liberty to ofier M. Brono-- 

 niart, with that respectful consideration, which I entertain for 

 the merits of so distinguished a philosopher. 



Observations upon the situation in which Organic Remains 

 are found. 



Among the observations which have been made upon the 

 position of organic remains, this certainly is a highly im- 

 portant one ; that different strata belonging to distinct rock 

 formations, or to the same formation, as is sometimes the 

 case, are distinguishable by means of vegetable and animal 

 remains, which appear to be peculiar to these strata, or at 

 least, are but rarely noticed in others. Thus we find in the 

 great coal formation, a large number of vegetable fossils pe- 

 culiar to this formation, and very unlike existing plants. 

 They are referable to the arundinacese, of which, some ap- 

 proach to the genera of the present day ; but a greater num- 

 ber belong to an order quite peculiar, and distinguishable by 

 the cortical part, which is covered entirely with regular im- 

 pressions arising from the petioles of the leaves. This dis- 

 cription of plants is supposed to have an affinity to the or- 



