50 DEPOSITS OF PHOSPHATE OF LIME. [bull. 46. 
generally consist of long fissures with parallel walls, while those of the 
second variety represent the irregular pockets described by Daubree. 
Tratat thinks that the ENE. and WSW. leads were formed first, and 
that those at right angles to them were formed later, by the action of car- 
bonic acid, which dissolved part of the original leads and redeposited 
it in new hollows and crevices. 
The phosphorite deposits are usually capped by a deposit of ferrugi- 
nous clay, containing pisolites of iron, bones of land animals, and nu- 
merous land and fresh-water shells. Among the bones are the remains 
of many carnivorous, herbivorous, and omnivorous animals, all mixed 
together. The bones are well preserved and not affected by chemical 
action. The deposits of Cregols and Beduer have afforded immense 
quantities of bones of carnivorous animals, and in the deposits of Eay- 
nal, Servanac, and Mouillac are found the remains of many skeletons 
of anthracotherium, palseotherium, and rhinoceros of several varieties. 
The bones are also occasionally found embedded in the phosphatic mat- 
ter itself. 1 Thus, near La Mandine there are so many remains of pala3- 
otherium (P. medium) that from one cubic decimeter of phosphatized 
marl four or five fragments of different jawbones and many other 
bones were obtained. Eemains of hysenodon and many land and fresh 
water mollusks, among them Planorbis and Limncza, as well as tur- 
tle remains, are found in many deposits. Bones of cainotherium and 
anoplotheriurn are of frequent occurrence. Though the rock which 
contains the phosphorite deposits is of Jurassic age, the phosphate 
itself is generally believed to be of early Tertiary (Eocene) age. The 
way in which the phosphorite came to occupy its present position, how- 
ever, has been a much more disputed point than the time in which the 
deposit was formed. Daubree, 2 Key-Lescure, 3 Leymerie, 4 and others 
are of the opinion that the phosphate came from mineral springs, 
rising from the bottom of the fissures. The phosphate was dissolved 
by the action of hot water containing carbonic acid, and, when it came 
into the fissures, the carbonic acid was lost and the phosphate was de- 
posited. They think the bones are too few to have anything to do 
with the origin of the phosphate. 
Filhol 5 urges against this theory that in all the deposits which have 
been worked out, and thus afforded a chance of examining the sides of 
the crevasse, he has found that the phosphate does not run into other 
leads by narrow necks and veins, as Eey-Lescure asserts, but that the 
leads are in no way connected with each other and that the crevices 
show no openings through the limestone which could have served as 
an exit for the phosphatic solution. Consequently he concludes that 
1 Mr. Daubrde: Comptes rendus Acad, sci., Paris, vol. 73, 1871. 
2 Alpli. Peron : Bull. Soc. geologique France, 3d series, vol. 2, 1874. 
3 Bull. Soc. geologique France, 3d series, vol. 3, 1875. 
4 Note sur les phosphorites du Quercy, Toulouse, 1872. 
5 Aunalessci. g6ol., vol. 7, 1876; Recherches sur les phosphorites du Quercy, pp. 1-220. 
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