MODE Till. ARGILLACEOUS GLUTENITE. 



iron ore. 4. Iron ochre, of a brown colour. 5. 

 Stalactitic iron ore, colour dark brown. 6. Earthy 

 matter, much charged with iron, seemingly arising 

 from the debris of other ores. The copper ores 

 are, 1. Friable and amorphous carbonate of cop- 

 per, colour rich green. 52. Beautiful carbonate of 

 an emerald green, crystallised in capillary fibres 

 of a silky lustre, diverging in radii from a centre : 

 this species is found imbedded in iron ore. 3. 

 Sulphuret of copper, disseminated through felspar 

 in some places, and in others, in great masses, in 

 iron ore. The rich carbonates were found near 

 the bottom of the mine."* 



This sand-stone also often occurs in a schistose 

 form, when it is called sand-stone flag. 



The Wernerians have confounded the sand- 

 stones, as they have the porphyries, while they 

 ought to be carefully distinguished according to 

 the nature of the cement. The whet-stones and Whet-stone, 



c. 



filtering-stones are often argillaceous glutenites, 

 as is the important division Cos of Wallerius, Lin- 

 naeus, and other writers in Latin. Some whet- 

 stones are curiously spotted, commonly with dark 

 specks on a light ground f. According to Wal- 



* Dr. Trail's Mineralogy of Shetland, in Neil's Tour, p. 170. 



t Da Costa, 120, &c. mentions the whet-stone of Derbyshire 

 as of a lax texture, easily pervaded by water, as most clays are. 

 The grind-stone of Gateshead, Durham, also possesses this quality. 



