NOME IV. JBASALTIN AND WACKEN. J"7J 



of ice, not to mention the heat developed by 

 crystallisation ; so that the agency of heat may 

 be conceived as admitted even by the Nep* 

 tunists. 



On the transition between Basaltin and Wac- 

 ken, the remarks of Daubuisson may also be 

 adduced. " We have already observed that ba- 

 salt has great connexions with the argillaceous 

 rock called wacken. Let us recollect those 

 prisms, of which one of the extremities is a true 

 basalt, while the other is an argillaceous sub- 

 stance, both being the evident produce of one 

 effort; a circumstance which excludes every 

 suspicion of a volcanic origin. This argillaceous Basaltin not 

 wacken cannot be considered as arising from 

 an eruption of mud ; for between it and the ba- 

 salt there is a most marked transition, there not 

 existing even a line between them. Nor can it 

 be said that this wacken is a decomposed lava ; 

 for at Scheibenberg, for example, the wacken 

 passes to common clay, which degenerates into 

 sand, and then into gravel; but a lava, when de- 

 composed, does not produce gravel of quartz."* 

 He adds in a note, that olivine, augite, &c. 

 though common in the basalt, are not found in 

 the wacken ; so that the latter cannot be a de- 



* Daub. Basaltes, 73. 



