492 DOMAIN^V. CALCAREOUS. 



calcareous muscles and clams. For the most 

 part, it only presents the impression of these 

 shells. In regard to the sand and flint, which 

 are found in the upper layers of the hill of 

 Montmartre, they have no peculiar character, 

 and do not appear to differ from those found on 

 the sides of rivers ; but in the masses of gypsum 

 is found whitish silex, striped, and formed in 

 this quarry, like the masses of shelly sandstone. 

 " In the hill of Belleville, two feet from the soil, 

 are found black flints, in beds formed in irregu- 

 lar heaps; they lie in a kind of marl, which 

 reposes on a bed of gypsum of ten or twelve 

 feet, the layers, which are of different thickness, 

 being intermixed with marl : this layer of gyp- 

 sum lies on a considerable bed of green argil, 

 under which the gypsum is again found*. 

 Bones. <c The bones which are discovered in the 

 gypsum, have undergone no other alteration 

 than that effected by time: the greater part 

 have a yellowish tinge. M. de Joubert has ob- 

 served, that these bones are always surrounded 

 with a kind of marl, which he regards as being 

 produced by the decomposition of the soft parts 

 of animals. In the cabinet of that naturalist 



* This green clay corresponds with that of the river Marne. 

 which is green. It contains iron. See Vauquelin's analysis. 



