EXPERIMENTS IN ICE MOTION. 927 
The most important feature of the experiment is shown in 
the sharp angulation of the recurved portion of the upper line 
and of the folding upon themselves of the lower with consequent 
stretching out in a series of detached portions. Fig. 7. 
Experiment 9 shows the same destruction of the lower line 
and a most remarkable elongated folding, also a recurving of the 
two upper ones as they arch over the last escarpment. Fig. 
8. The advanced position of the rear of the upper lines is 
another evidence of the drag. 
Experiment 10 shows identical phenomena with sharply angu- 
lated recurve just rising over an escarpment. Fig. g. 
Experiment 11 shows another form of the loops in passing an 
escarpment and the stretching with consequent approximation of 
the two ends of the loop caused by the horizontal progression of 
lee Wee LENSE NO), 
The effect produced on the loop by progression on a plane 
surface is clearly exemplified by the basal line in Figs. 7, 
opandso; and ine the loop atthe extremity yor Figs 10s) ihe 
action is to produce a stretching and close refolding of the loops, 
then a breaking up of the loop into sections. The result is the 
formation of laminz, not of great extent themselves but in series 
of great extent. 
It is necessary to again call attention at this point, to the 
phenomena shown in Experiment 5, Fig. 44. The basal, dirty 
layer of the wax, upon reaching the summit of a rounded obstruc- 
tion did not follow down the far side of the obstruction, but was 
carried forward in a straight line into the body of the wax leav- 
ing a portion of the rear of the obstruction untouched. 
RELATION OF THE EXPERIMENTS TO OBSERVED PHENOMENA IN ICE. 
While the author was engaged upon these experiments Pro- 
fessor Chamberlin, in his annual address as president of the 
Geological Society of America (Recent Glacial Studies in Green- 
land, Bull. Geol. Soc. of Am., Vol. VI, p. 199) reported his 
observations of the previous summer on the glaciers of Green- 
land. 
