530 DOMAIN V. CALCAREOUS. 



A pudding-stone of fragments of black horn- 

 stein in a gluten of clay, iron, and lime*. 



The chief specimens have been already indi- 

 cated. 



STRUCTURE II. SMALL GRAINED. 



Calcareous sandstones are regarded as common. 

 That of Fontainebleau, which is commonly rec- 

 koned calcareous, does not, by Brongniart's ac- 

 count, always effervesce with the nitrous acid ; 

 but only that of two quarries, Bellecroix and Ne- 

 mours, in which the curious crystals are found. 

 The others afford siliceous sandstone. 



The sandstones which present zones of different 

 colours, and dendritic delineations, seem to be 

 chiefly argillaceous, the clay cement being im- 

 pregnated with iron. Calcareous sandstone often 

 alternates with limestone, and is ascribed by many 

 Sites. to the same formation. It is the most common of 

 all the sandstones, and forms long chains of hills, 

 from Osnabruck down to Hessia, and along the 

 Rhine. It also constitutes the base of the Can- 

 ton of Berne, and rises into considerable moun- 

 tains in the south of France, particularly that of 

 Caume, on the north of Toulon, which consists 



* 1099, i94i, 1*39. 



