STEVENSON— INTERRELATIONS OF THE FOSSIL FUELS. 37 



Conferventorf, from free-swimming plants, Confervse, Naiads, etc., 

 Haidetorf, heath-peat from various heaths, largely Erica tetralix, 

 Holztorf, mostly from mouldered stems of trees, 

 Meertorf, from seaweeds, is of rare occurrence. 



No one of these forms, except very rarely, is found as the mass 

 of a bog, but all may be seen in the vertical section of a single 

 deposit, indicating variations in conditions- during growth. Zirke! 

 gives also the ordinary terms designating difference in composition 

 or structure ; 



Pechtorf is pitch black to brownish black and is apparently almost 

 homogeneous ; the plant remains are so changed as to be prac- 

 tically unrecognizable and the material, when dried, is very 

 similar to Tertiary Pechkohle. 



Rasentorf is yellowish brown or wood-brown and the remains of 

 plants are distinct. 



Fasertorf designates fibrous remains of plants, penetrating the 

 Pechtorf. 



Papiertorf is wood- or soot-brown, with the remains of plants little 

 changed and in separable layers. 



Torferde is a peaty earthy substance, friable and with few recogniz- 

 able plant remains. 



Baggertorf is a black-brown, pulp-like peat, obtained by dredging ; 

 it dries to a hard mass showing no vegetable structure. 



Vitrioltorf contains much ferrous sulphate. 



Some of these terms are unimportant, but others are of wide 

 application, designating types which have been considered in all dis- 

 cussions. Von GiimbeP* introduced a number of new terms, several 

 of which have come into general use. For Pechtorf, he prefers 

 Torfpechkohle, which is the Dopplerit of Haidinger ; instead of 

 Baggertorf, he suggests Specktorf and for Papiertorf, Blattertorf. 

 For Fasertorf he would substitute Torffaserkohle ; the former term 

 is employed by several writers as descriptive of the felted mass of 

 peat so that it is not definitive. The Conferventorf of Zirkel is 



-* C. W. V. Giimbel, " Beitrjige zur Kenntniss der Texturverhaltnisse der 

 Mineralkohlen," Sitz. d. k. Bayer. Akad. d. JViss.. 1883, pp. 128-134. 



