292 PEOFESSOR TYNDALL ON THE VEINED STEUCTLTIE Of GLACIERS. 
Towards the right of the fall, looking upwards, this wa^ particularly the case ; for here 
no pressure had been exerted upon the beds sufficient to contort them or to rupture 
their continuity. . 
The tisui-e of a vast lake pouring its waters over a rocky barrier, which curves con- 
vexly upwards, thus causing the water to rash down it, not only longitudinally over t e 
vertex of the curve, but also laterally over its two aims, will convey to the mind a tole- 
rably correct conception of the appearance of the fall. Towards the centre the ice was 
powerfully squeezed; the beds were bent, and their continuity often ruptmed, so as to 
exhibit faults; but they were as plain, and as easily traced, as in any other portion o 
the fall. I thought I saw structural groovings running at a high angle to the strath- 
cation. Had the question been an undisputed one I should have felt sure of t us, or 
the moovings were such as always mark the stnicture. The place bemg dangerous, 
fost^observed it from a little distance through my opera-glass; but at leng*, resihnng 
the instrument to my guide, and leaving him to watch the tottei-ing blocks overhead, 
and to give me warning in case of their giving way, I went fonvard to the b^e of t e 
fall, peeled the grooved surface away with my axe, wA found the true veined strudme 
midemeath, running, in this case, nearly at right angles to the stratificariom 
The superficial groovings were not uniformly distributed over the whole tace oi the 
terrace but occurred here and there where the ice had yielded most to the pressure, 
examined several of these places, and in each instance found the superficial groovmg to 
be the exponent of the trae veined structure underneath, the structure being in genera 
nearly urfcal, while the lines of bedding were horizontal. The coarse_ bands which 
marked the division of the beds were also seen underneath, when the surface of he ice 
was removed. Having perfectly, and with deliberation, satisfied myself of these larts. 
made a speedy retreat; for the ice blocks were most threatening, and the time of dav 
that at which they fall most frequently. 
We now resolved to tiy the ascent of the glacier to the right ; it was much riven, bm 
perfectly practicable to a good iceman. To me it was also perfectly dehghtlul , m tact, 
as regards the relationship of structure and stratification, this glacier taught me more 
than all the othera I had visited taken together. Our way lay through fissures w nc i 
exposed magnificent sections, and every step forward added further demonstration to 
what I had already observed at the base of the fall. The bedding was perfectly distinct, 
and the structure equally so, the one being at a high angle— sometimes at a rig it ang c 
—to the other. Among these crevasses the pressure was in some cases greater than on 
the fall, and the structure proportionally more pronounced. The crumpling o t le e 
demonstrated the exercise of the pressure, and the structure went straight through such 
crumplings, thus furnishing me with numerous parallels to the case observed by 1 lo- 
fessor Sedgwick, Mr. Sorby, and others, of the passage of slaty clea^age thiougi con 
torted beds Indeed I question whether the phenomena of cleavage and bedding, in 
the case of slate rocks, were ever exhibited, side by side, with a distinctness equal to 
that of the stratification and “ structure” of ice in the present instance. 
