98 



EARTHS. CALCAREOUS. 22. Marga. 



Marl ^hoTnfon chem. 3. />. 614, 



Argillaceous Mar'e. So^cverhy Brit, mtn, tab, 14. 



1. Argillaceou?, lubricou?, friable, plaftic. 

 I'Vall-fyst. TTiin, I. p. 69. n. I. 



2. Argillaceous, conipa£l, dry, pure, with very fine particles, 

 IValLfsst. mm, I, ^, 71. «. 2. 



Smc<5lis~fubtilis, Carth. miu. p. 7, «. I. 



3. Cretaceous, loiling the fingers, 

 IFall Jyst, mln. i. ^. 72. «. 3. 



4. Mixed with arenaceous particles, crumbling to powder in the 



air, a little greafy. 

 WalLjyfi. min, 1. /. 72, ». 4. '**' 



Found in almoft every country in Europe^ in ftrata : colour 

 whitifh, yeliowi(h-white, or yellowifh-grey, and grows paler 

 in drying : fomctimes found mixed with Mica gypfum or 

 ^ fand, in the latter cafe it is fuiihlc into a tranfparent glais, 



fometimes impregnated with iron, vesy rarely with other 

 metals: generally contains from 60 to 80 percent, of mild 

 carbonate of lime, the remainder of alumina or clay : fpecific 

 gravity from 1,600, to 2,400. 



nilotica. Farinaceous, bfownifh, cinereous when burnt, mixed with 



mould. 



Argiila raixta humo. S^st. nat, xii. 3, p, 205, n. 19, 

 Argilla fubfuica. Muf.TeJf. no. 



2. Vitrifying. Wall, mln, p. 3 1 . 

 Wall, Jy St, mitt. I. ^. 75. «. 6. 



Found in the plains of E?jpt annually overflowed \:>y the waters 

 of the Nile, where it is left by depofition after their recefs, 

 and is highly fertile. 2} In Upland in Sweden, 



fatiscens^ Very foft, fiflile, greyilh, crumbling to powder in the air. 



Schiftus margaceus. Ssyst. nat xii. 3. p, 38. «. 8, 



Marga iadurata fatifcens. Cronst. -min, fed, 27. 



Marga ind. fiff. WaiLfyst min. i. ^. 73. ». 5. 



Found in thicker or thinner itrata, in S^vedent Gtrmariy and 

 heivitzeriandt ofcen between calcareous itrata : colour veilow- 

 i(h, greenilh, blueifli, with often a rufous tinge. 



porosa. Indurated, porous, precipitated from waters, breaking 



into indeterminate fragments- 

 Tophus Ludus. Syst, nat. xii. ^, p, 186. «. !♦ 

 Porus aqucus folidus. Wall. min. "^t^x* 

 Tophus foiidus. Wall.fyst, min, z, p. 394. n. 17. 



2. Tophus argillaceus. Syst. nat xii. 3. p. 190. ft, 17, 

 Indurated calcareous marL Kiravan miner, i, p, 95 

 Indurated marl, Schmijier min, i. />. 229, 



