254 DOMAIN III. ARGILLACEOUS. 



found ammonites in the argillite near Meyrin- 

 gen, in Swisserland. 3 Helv. Mag. 191. In a 

 specimen from Hessia, mytilites occur: see 

 Leske, G. 339. Voigt found a lime-stone, with 

 petrifactions, between strata of argillite. 1 Mi- 

 neral. Abhandl. 86, 87, 88. It often contains 

 piscine remains betwixt its lamina?. Lasius, 105. 

 Saussure found argillitic strata intermixed with 

 black marble. 1 Sauss. 401. In the Hartz, im- 

 pressions of reeds, rushes, and pectinites, are 

 found on it where it adjoins to rubble stone. 

 Lasius, 103. 105. Sometimes it hardens, and 

 grows more siliceous, from the bottom upwards. 

 Lasius, 105. Sometimes it is harder at greater 

 than lesser depths. Idem, 102. In the Hartz it 

 alternates with, and sometimes is intimately 

 mixed with, rubble stone. Lasius, 138. It also 

 passes into sand-stone. Idem, 105. At Kinne- 

 culla it alternates with aluminous slate and 

 marlite. 29 Schwed. Abhandl. 26."* 



In the account of siderous slate it has been 

 observed that it contains from 10 to 20 of iron. 

 Dr. Townson has given an analysis of argilla- 

 ceous schistus, or clay slate, being argil 25, 

 silex 60, magnesia 9, iron 6, and some petro- 

 leum f. The last is accidental, and he perhaps 



* Geol.Ess. 241. 



t Philosophy of Mineralogy, p. 57. 



