360 M. Hoffmann on Valleys of Elevation, 



this nature which still exist in several of these valleys, are only 

 the last ramifications of this great phenomenon. 



M. de Buch has also tried to show, that when hot springs 

 issue at the bottom of crevices and hollows, the carbonic acid 

 which accompanies their eruption escapes through the rents of 

 the formations, and impregnates the cold springs in higher places. 

 The observations of these two naturalists tend to support the 

 opinions exposed by M. Rozet, in his memoir on the old alluvia 

 of the valleys of the Rhine. 



Of the phenomena which clearly indicates the elevation and 

 fractured state of the chains of Westphalia, one of the most re- 

 markable is the formation of certain valleys, which we shall 

 name circular valleys, or valleys of elevation. Their principal 

 character consists in their having been originally shut in on all 

 sides by precipices, whose strata are circularly inclined. The 

 most striking example of this formation is the valley of Pyr- 

 mont, as represented at Figs. 1. and 2., Plate IV. 



The upper edges of the muschelkalk mountains, which form 

 the surrounding precipices, are seen on the opposite declivities, 

 and are sometimes half a mile distant from each other, and they 

 rise above the bottom of the valley, equally on all sides, to a 

 height of from 900 to 1000 feet. Upon this formation are seen, 

 sometimes at greater heights, the edges of the keuper, which 

 has also been pushed backwards, and the first mountain's form, 

 in the ridges of the Winterberg, Arminiusburg, the Schwalen- 

 bergerwald, &c. a second girdle, much less entire, around the inner 

 wall of the valley. In the bottom of this valley, the variegated 

 sandstone is seen issuing beneath the cliff's of muschelkalk, and 

 rising to a height of 400 feet. The upper limits of this last group 

 do not attain the same elevation on the opposite slopes ; on the 

 contrary, they are seen rising much higher on the north and east 

 sides than on the others; and, conformably with this arrangement, 

 the inclination of the strata is greater on the two first sides than on 

 the last. I found, for example, on the north side of the Bamberg, 

 the upper limits of the variegated sandstone at an absolute height 

 of 849 feet, and the inclination of the superimposed muschel- 

 kalk was from 20° to 24°. Right opposite, in the Muhlberg, 

 on the contrary, the limit occurs at 540 feet, and the inclination 

 of the limestone is very slight. In like manner, in the western 



