MODE XIV. CALCAREOUS GLUTENITE. 531 



of alternate beds of limestone and calcareous 

 sandstone*. 



According to Patrin, the sandstone of Fontaine- Of Fontaine- 



bleau. 



bleau is always a calcareous glutenite ; but when 

 he praises its utility at Paris, where it is employed 

 in paving the streets, he forgets that it wears out 

 in three years ; while granite might be had from 

 Cherbourg, which would last thirty. This cele- 

 brated sandstone sometimes forms regular beds, 

 and sometimes only appears in blocks, dispersed 

 in heaps of pure quartzy sand, upon which the 

 gluten does not seem to have acted. For Rom& 

 de Lisle has long since remarked, that such sand 

 is often a pure homogenous production of nature, 

 which must not be confounded with those pro- 

 ceeding from decomposition!. The formation of 

 this stone seems illustrated by the noted crystals, 

 which, though composed of quartzose sand, as- 

 sume the rhomboidal form of calcareous spar; 

 and some even present crystals of a beautiful yel- 

 low spar, quite transparent. Perhaps it was in a 

 different quarry, that Lassone made the singular 

 remark, that the new surface, at the end of some 



* Patrin, iii. 324. He seems singular in his opinion that the 

 building stone used at Paris is a calcareous sandstone, while aJl 

 others regard it as a konite. See Brongniart, art. Moellon t i. 204. 

 It is the chaux carlonatte grossiere of Hauy. 



f ii. 63. 



2 M <2 



