. III. DIST. CHAR. Substance. 149 



the copper mines of Siberia. Many of these, 

 however,, are rather impregnations, than com- 

 plcts mineral substitutions : in others, little or 

 no part of the original wood remains,, while its 

 texture and form are preserved, with the most 

 perfect exactness, in the substituted ore. 

 IRON ORDER. 



Argillaceous Iron-ore. 



Common Common Clay Ironstone, James, p. 

 326. F. An. & Veg. most commonly the 

 latter the animal forms it assumes are ge- 

 nerally those of fluviatile shells. 

 Nodular Reniform Iron-ore, James, p. 329. 

 F. An. & Veg. mostly the latter. 



Bog Iron-ore. James, p. 334. F. Veg. rarely 

 An. The lowland, or bog iron-ores, frequently 

 exhibit specimens of petrified wood, particu- 

 larly in certain parts of the Russian empire, v. 

 Tooke's View of theRuss. Emp. V. 1. 



Sparry Iron-ore., Kirw. p. 130. F. An. We 

 have had specimens of fresh- water shells in 

 this substance The matrix an argillaceous 

 iron-ore. 



Blue Martial Earth. Kirw. p, 185. This sub- 

 stance is common in peat soils ; but though fre- 

 quently incrusting, rarely forms, the substance 

 of the vegetal reliquium We have sometimes, 

 however, met with it assuming the form of 

 small, fibrous roots, &c. 



Iron- Pyrites. 



Common. James, p. 253. F. An. & Veg. 



