Travels of a Naturalist in the Alps. 297 
His journeys were prosecuted during the years 1828 and 29; and 
the work in its numerous maps, geological sections, and tables of me- 
teorological observations at various remote and elevated points, evin- 
ces an extraordinary activity, while its details make known some of 
the most toilsome and hazardous adventures recorded in the history 
of geology, probably not excepting those of Saussure. 
Unaided by the sections appended to the volume, it is difficult to 
do justice to the author’s geological observations. With a view how- 
ever, to render intelligible the general structure of the Bernese Alps, 
we give the following description of the strata from the Lauterbrun- 
nen valley to the summit of the Jungfrau. 
1. Lowest, proper granite, including strata of gneiss and mica slate. 
2. Alpine limestone, (Muschelkalk). 
3. Greywacke interposed formation, (Wacke). 
4, Lias. 
5. Secondary granite, (High granite). 
The lowest of these limestones, or that which rests immediately 
upon the primitive granite is characterized as follows: Its color is 
ash or smoke grey, sometimes with a shade of blue or red, but 
wherever in contact with the granite it is white. More rarely it is 
black, in which case it becomes siliceous and is veined with Calcare- 
ous Spar. Its fracture is even, and mostly large conchoidal, except- 
ing where in contact with granite or gypsum, when it becomes gran- 
ular. It is considerably siliceous, frequently bituminous, and is regu- 
larly stratified in thin layers. It is a remarkably uniform formation, 
suffering no other transition than into a white granular dolomite 
when in contact with the proper granite. ‘The thickness in some 
places is very great, while in others it is very thin, in which case, it 
contains petrifactions. 
Next in the ascending order, occurs the interposed formation, con- 
sisting of a pisiform iron stone, a granitic sandstone (composed of 
_ granitic materials) and a porphyritic greywacke. Its commence- 
ment and progress, from below upwards, is thus described. At 
first the lime begins to diminish, being replaced by alumina and ox- 
ide of iron. It is only in the highest strata of the Alpine limestone that 
organic remains begin to occur, such as Ammonites, Mytilites, Tere- 
bratulites, &c. At this point, the limestone formation must be re- 
garded as having reached its termination. Suddenly organic depo- 
sitions cease; and the strata pass into a quartzose pumice-like con- 
glomerate, held together by a calcareous cement. Grains of feld- 
Vol; SX VILE No.2.) 38 
