IS 14.] An Account of the Basalts of Saxony. 145 



lenberg, the basalt rests immediately upon sandstone; in Steinkopf, 

 Geissingenberg, and Luchauerberg, it rests upon porphyry; ia 

 Spitzberg it rests upon mica slate; in Jjichtewalde, Stolpen, and 

 Lendscrone, it seems to rest on granite; and in Heidelberg- it rests 

 upon gneis-. 



Fmm bis examination of the structure of the basaltic mountains 

 of Saxony, Daubuisson draws the following conclusions. The 

 basall evetfy where forms' the uppermost rock ol these mountains. 

 No traces of it coming from below can be observed. Hence it 

 must have been formed from above, and of course must have been 

 the last formed of all the rocks, and probably loug ai'er all the 

 other rocks constituting these mountains had existed. Basalt pos- 

 irnilar characters with other rocks, and therefore may have 

 been formed in the same way with them. It is composed of the 

 same constituents as greenstone, and gradually passes into green- 

 stone on the one hand, and wacke on the other, lie. conceives the 

 basalt lo have once constituted a bed which covered the whole 

 country, and to have been all wasted away except the few fragments 

 which now cap the summits of some of the hills. 



In the fourth part of his work Daubuisson refutes the opinions of 

 those who consider the Saxon basalt as having 'flowed from a vol- 

 cano. Two hypotheses on this subject present themselves. We 

 may either suppose that each basaltic mountain has been a distinct 

 volcano, or we may suppose that all the basalt of Saxony has flowed 

 from one great volcano which now no longer exists. The author 

 shows that these basaltic mountains can never have been volcanoes, 

 because there is no analogy between them and volcanic mountains. 

 They are regularly stratified, which is never the case with volcanic 

 mountains ; no traces of a crater can be perceived, nor any thing 

 similar to the lava vomited out of volcanoes, unless the masses of 

 basalc, the position of which is not such that it can have been in a 

 state of fusion, be considered as such. We cannot, then, with any 

 shadow of probability, allege that these basaltic mountains have 

 . volcanoes. The notion that the basalt has flowed from a single 

 crater now no longer in existence is still more absurd, if possible. 

 No traces of ashes, scories, cinders, can he any where observed, 

 though these mountains have been every where explored for centu- 

 ries, so that the interior is nearly as well known as the exterior. 

 '1 he basalt, if lava, must have been the result of one eruption 

 h covered the whole surface of the mountains, to an extent of 

 600 square miles, with an even bed bf basalt nowhere more than 

 .',oo feet in thickness. Such a supposition is obviously absurd, and 

 quite inconsistent with the nature of lava, or with the common 

 principles of hydrostatics, by which the motion and figure of lava 

 (1. Prom tli iderations our author conceives 



lupposition that the Saxon basalt has proceeded from a volcano 

 ther untenable. 

 Ourauthi r next considers the origin of basalt in general, and 

 i show (hat it could not possibly have been produced 

 Vu l\ , ii K 



