8 M. Bourdet on the Fossil Bones 



It is in this sandstone and at Beauchamp to the E. of Pi- 

 errelaie that MM. Gillet de Laumont and Beudant have ob- 

 served terrestrial and fresh-water shells (well characterized 

 Limnei and Cydostomce) mixed with the above-named marine 

 shells. 



It results from the preceding observations: 1. that the fos- 

 sils of the calcaire grossier have been deposited slowljf and in 

 a tranquil sea, since these fossils occur in regular strata, are 

 not mixed, and the greater part are in a perfect state of pre- 

 servation; notwithstanding the delicacy of their structure, even 

 the points of the spiny shells being entire ; 2. that these fossils 

 differ entirely from those of the chalk ; 3. that as the beds of 

 this formation were deposited, the species changed, many dis- 

 appeared, while new fossils took their place, which would ren- 

 der a long series of generations of marine animals probable ; 

 and lastly, that the number of species continually decreased, 

 until they finally disappeared. 



2. On the Position of the Fossil Bones of Mont de la Moliere 

 {S-mtzcriand\ hy the late Mons. P. F. M. Bourdet*. 



The author commences with a description of the rocks 

 in the vicinity of the mountain in question, which he visited 

 in June 1823. " The beds," he says, "are composed, 1. of 

 veo'etable soil; 2. of nine feet of a soft sandstone (jiagel-Jluh 

 sand), which easily decomposes in the air ; 3. of eight inches 

 of a species of coloured fuller's-earth-marl, employed by the 

 clothiers of the country; 4. of the same thickness of a liard 

 calcareous sandstone ; and 5. of a chocolate-coloured and hard 

 aro-illaceous marl. The remainder is concealed by fallen por- 

 tions of the upper beds ; the debris of a molasse sandstone. 

 Advancing towards the hill, the slope of which is very gradual, 

 two distinct rocks are seen beneath the vegetable soil ; the first 



* From a notice in Baron de Ferrusac's Bulletin des Sciences, (a very 

 valuable periodical publication,) of the Author's paper in the Ann. de la 

 Soc. Linneenne de Paris, Sept. 1 825i 



" This memoir is highly interesting, as it presents us \vith a well authen- 

 ticated instance of the bones of the hyaena, the elephant, the rhinoceros, 

 &C.J having been found lower down in the series of formations than the di- 

 luvium, mixed up with marine, terrestrial, and fresh-water shells ; a very 

 valuable geological fact, in addition to that, now some time known, of the 

 teeth of the mastodon (not the great species) having been discovered 

 among the lignite of some of the Swiss saiidstones. Specimens of the lat- 

 ter I had the pleasure of seeing at Prof. Meisner's at Berne a few years 

 since. As my friend Dr. Buckland intends elucidating this subject from 

 observations made in Italy, &c., I shall abstain from further remark. 

 M. Bourdet considers the compact sandstone-rocks of Monte de la Moliere 

 as referable to the marine? gypsum formation of the environs of Paris." — 

 Tratis. 



is 



