122 EARTHS. ARGILLACEOUS. 34. Cariofus. 



Found on the banks of the 72^/«^, principally near Ai^dernach 

 and on Mount Vc^elhur^^ Ijine feet unJer tlic furfac, where 

 ftreams of water have n')t h-id accefs, duil grey or blackifli, 

 rarely variegated : furfate roi^gh and porous: fra(fture com- 

 monly earrhy, rarelv lamellar : it coniains fragments refem- 

 bling pumice, cryllals oi hornMende, mica, cl:y, ihte, 

 quartz, marble, iron ore. <ind other {ubflai'ces : \\'h<x\ pound- 

 ed it makes the bell cement ior buildings uuder vvdter, 



columnar e. Prifmatic. 



1. In 6 fiJed prifms. 



2. In 5-nded prifms. 



Found on the br-nks of the "Rhine^ and fometimes near the bafe 

 of Mount Efncy in columnar mafles of a grey or Ifabella-yeU 

 low colour, iianding clofe to each other, and forming inter- 

 nally one common mafs. 



34. CARIOSUS. Confiding of alumina, filica, and 

 carbonate of lime, with a fmdl portion of iron : 

 light, foft, porous, falling to powder in water: 

 effervefcing with nitric acid, hardening and grow- 

 ing a little red in the fire. 



anglicus% Cariosus. Rotten-Jlone. 



Tripela cariofi. Wall.fyji. min. I. p. 92. n. 2. 



Crcta fufca terra cariofa didla. Da costafof, 87. 



Found in Derhyjhirey Glamorgan/hire t and other coal countries, 

 generally over veins of coal : colour Ifabclla-yellow, dull 

 grey or brown : it eafily moulders in the-open air, and foon 

 falls to powder in water, for which reafon it has been deno- 

 minated Rotren-ftune. It is principally ufed far polilhing 

 metals and other fubitances. 



