Page:Quarterly Journal of the Geological Society of London, vol. 27.djvu/456

 mountain nearly level at the top, which derives its name from a singular hollow, nearly two miles in circumference and 1000 feet deep, lying near to the summit." To this I add my own note*. " It is excavated in a mass of banded limestone and shale, the strata lying horizontally in the face of the cliff, except at the more southern extremity, where they curve upwards. All down the cliff are distinct traces of the erosive action of many streamlets. The floor of the valley below is a level basin, as though it had once held a lake." This was written at the railway station, whence there is a fine view of the cirque.

Am Ende der Welt, Engelberg. — This cirque is at the termination of the Horbis Thal, a glen descending into the Aa valley just above Engelberg. Less grand than either the Fer-a-Cheval or the Creux de Champs, it is still a striking object, and exhibits the same peculiarities of a comparatively level floor, of enclosing precipices, and of numerous waterfalls. The strata in the precipices, which are perhaps about 1500 feet high, are moderately horizontal on either side, but much contorted in the middle. The walls of the cirque, when it is viewed from the lower end, appear to be crowned with sloping alps, and these to be surmounted with a line of limestone crags. Speaking more correctly, it forms a sudden step or break in the level of an upland valley which lies between two great spurs of the Rothstock massif, and carries the drainage of the Graussen glacier to the Aa.

It would be easy to multiply examples of cirque-like glens, similar though inferior to these ; but as they would exhibit no fresh features of importance I pass on to my last case, which satisfied me that only one explanation could be offered of their formation.

The Cirques of the Rothstock. — As the traveller bound from Engelberg for the Surenen Pass gains the rugged pastures of the Blacken Alp (5833 feet), he sees gradually opening but on his left hand, not one, but two fine cirques cut out of the highest part of the Rothstock massif. They are separated by a spur from the peak named Rothschutz on the Federal Map, and are very similar in appearance, though the eastern one is on the whole the finer of the two. Its other extremity is the Blackenstock (9587 feet), and from this summit to the Rothschutz (9278 feet) runs a line of crags not much inferior in height. The chord joining these two points is about 2800 yards long, and the sagitta of the arc about 650 yards ; but the spurs projecting from the two extremities give a more semi- circular appearance to the cirque than these measurements would suggest.

Above the usual taluses of debris rises a high band of cliffs of a hard yellowish-grey limestone, which supports a still loftier belt of a reddish rock, doubtless a rather sandy and coarse calcareous shale ; over this is a sort of terrace-shelf or slope, hollowed out into small combes ; and then rises another barrier of limestone cliffs, forming the lip of the cup-like hollow. Clouds prevented me from seeing the sky-line in more than one place ; but it is nowhere more than a few hundred feet below the peaks named above. For the same reason, I


 * Central Alps, p. 5.