O02 Capt. Marshall Hali—Glacier Observations. 
‘“When the ice is in retreat, the marks of its further recent ex- 
tension are seen fringing the glacier both at the ends and sides in 
their lower portions, the glacier fails to fill its former bed, and bare 
stony tracts, often interspersed with pools or lakelets, lie between 
the end of the glacier and the mounds of recent terminal moraines. 
‘“‘ Where a glacier has retreated to any considerable extent, careful 
observations of the form of its bed are of value. What is the nature 
of the rock surfaces exposed—convex or concave; are they rubbed 
smooth on their leesides; how far have the contours of the cliffs or 
slopes, or the sides of any gorge, been modified where they have 
been subjected to ice-friction? Is there any evidence that the ice 
has flowed over large boulders, or loose soils, such as gravel, with- 
out disturbing them? How has it affected rocks of different hardness, 
for instance, veins of quartz in a less hard rock? Generally, do the 
appearances indicate that the glacier has excavated, or only abraded 
and polished its bed; that it has scooped out new rock-basins, or 
only cleaned out, scratched, and preserved from filling up by alluvial 
deposits or earthslips, existing basins? Whatis the general character 
of the valley bottom and slopes above and below the most con- 
spicuous ancient moraines ? 
“The depth of mountain lakes and the position of the point 
of greatest depth should be ascertained wherever possible. ‘The 
marginal rock structure of lake basins, particularly near their outlet, 
is of much importance with a view to ascertaining whether they are 
true rock basins, or whether they are reservoirs formed by ancient 
moraines, earthslips, or alluvial deposits. 
“The traveller or surveyor should, if possible, paint a mark and 
date on any conspicuous rock in situ parallel with the termination of 
the glacier at the time of his visit, marking the distance in yards of 
the ice from it. The next visitor will then be able to measure the 
movement that has taken place since his predecessor’s visit. Leaving 
out of question elaborate trigonometrical methods, such, for instance, 
as have been carried out on the Rhone Glacier in Switzerland, the 
following plan gives very valuable results, and demands no other 
instruments than a small jar of paint, a brush, a measuring tape, and 
a pocket compass. To ascertain the recent retreat of a glacier, 
measure the distance from the end of the ice in front of the longi- 
tudinal axis of the glacier to the most advanced terminal moraine, 
where vegetation first shows itself. The bare ground recently left 
by glaciers is easily recognisable. The diminution of volume is best 
measured by ascertaining the height of bare soil left on the sides of 
the lateral moraines in the portion of the glacier within the zone 
of vegetation. All photographic representations of the glacier end, 
and of the ground which has been freed from the glacier ice, are of 
great value. Those will be of most service that show the position 
of the glacier-snout with relation to some conspicuous rock or other 
feature in the local scenery. Hach photograph should be dated, and 
the bearings and distance of the camera with reference to any such 
feature accurately noted. 
“Tt is very important to investigate the state of various glaciers 
