STEVENSON— INTERRELATIONS OF THE FOSSIL FUELS. 175 



from a conifer, which Conwentz has named Piinis succinifera. The 

 resiniferous organs were mostly in the bark and twigs but were 

 abundant even in the w^ood itself. The conditions in these old forests 

 were very similar to those observed in conifer forests of Bohemia : 

 there could have been hardly any sound trees in the old Bernstein 

 forests ; wind, weather, saprophytes and other plant parasites, in- 

 sects and other animals caused injury and led to flow of the resin. 

 Bernstein is complex, consisting of gedanite, soft, yellow, trans- 

 parent and fusing at about i8o° C. ; glissite, brown, opaque; stantie- 

 nite, black, tender, brittle ; bechanite, brown, tender, brittle ; suc- 

 cinite, transparent, lustrous, yellow, brittle, fusing at 250-300° C. 



The resemblance of these resins to some of recent age is very 

 great and the origin is similar. They are exudations from coniferous 

 trees and are resistant to decomposing agents, so that the propor- 

 tion becomes greater as the process of decomposition advances in the 

 vegetable material. Amber is associated, at times, with fragments 

 of the trees whence it was derived, but in many places, as is the 

 case with the recent kauri and copal, the woody materials have dis- 

 appeared, leaving the resin free in the sands. 



Pyropissite is locally characteristic of Oligocene coals in much 

 of the Sachsen area of southern Prussia, where it, as well as Schwel- 

 kohle, a mixture of pyropissite and fuel coal, is distilled for the 

 paraffins ; it occurs also in the Miocene and Eocene of other regions. 

 Karsten,-*^ in a brief communication to the German Geological So- 

 ciety, described it as a peculiar earthy brown coal, w^hich forms the 

 roof of a bed near Weissenfels as well as of one near Helbra, be- 

 tween Mansfeld and Eisleben. It passes gradually into the ordinary 

 brown coal, has gravity of 0.9 and leaves 13.5 per cent, oi ash. At 

 from 100° to 125° C, it gives off a heavy white vapor and at red 

 heat the product is an oily liquid. Stirred in an open vessel, the 

 whole mass liquefies and becomes pitch-like ; in burning it gives oft' a 

 disagreeable odor. The composition, ash and water free, is carbon, 

 68.92, hydrogen, 10.30, oxygen, 20.78, while that of the associated 

 brown coal is carbon, 64.32, hydrogen, 5.63 [oxygen and nitrogen, 

 30.05]. The last two constituents are not given by Karsten. 



24-iKarsten, Zcitsch. d. d. gcol. GcscU., Bd. II., 1850, p. 71. 



