174 STEVENSON— INTERRELATIONS OF THE FOSSIL FUELS. 



the bituminous grade. The scanty notices of PHocene coals contain 

 few references to resins, the only definite note being that by Hutton 

 respecting New Zealand, in which he states that the coal often con- 

 tains large lumps of retinite. Thiessen found much resin in the 

 Miocene coal of Monte Diablo of California; Brown and Potonie 

 note the considerable proportion of resins in the coals of Greenland 

 and southern Prussia. The Oligocene coals of Germany and British 

 Columbia are rich in resin and, at times, it is found in cavities within 

 fossil wood. Eocene coals throughout, when they are lignite or sub- 

 bituminous, are notably resinous, material of that type occasionally 

 composes a great part of the mass. The term retinite is employed 

 frequently as a group name, but the resins are many. Amber or 

 Bernstein, the best known popularly, has been reported from numer- 

 ous places, widely separated. Dall states that it has been obtained 

 at many points in Alaska ; Daubree observed it in the Bas-Rhin 

 province and Potonie says that it is abundant at Senftenberg. But 

 this mineral occurs in commercial quantity chiefly on the Baltic coast 

 of Prussia, where, according to Karsten,-*- it is procured by digging 

 and by dredging. In the former process, the recent sands are 

 removed and the underlying clay shales, known as " amber veins," 

 are exposed, in which are nests of brown coal and amber, apparently 

 much compressed. These overlie coarse greenish sand, under which 

 the important deposit is reached. This, with the overlying sand, 

 extends under the sea and is the source of the amber, which is 

 thrown on shore by the waves or is obtained by dredging. 



Potonie-*^ states that Bernstein occurs over the whole of Xorth 

 Germany, Poland, Russian Baltic provinces and Finland as well as 

 in many other regions ; but it is most abundant in Sammland, near 

 Konigsberg. There it occurs at three horizons. The original deposit 

 is now below the sea, whence it is washed up by the waves ; but 

 these Eocene beds were gashed by glaciers and now the mineral is 

 found also in glacial drift. The Bernstein forest grew on Creta- 

 ceous debris. This fossil resin, originally fluid, is an exudation 



242 H. Karsten, "Ueber das Vorkommen des Bernsteins an der preussische 

 Kiiste," Karsten's Archives, Vol. 2, 1830, pp. 289, 290. 



243 H. Potonie, "Der baltische Bernsteins," Natur-Wochcnsch., Bd. VI., 

 1891, pp. 21-25. 



