720 ALLEN DAVID HOLE 
II. In the case of (3), (4), or (5), percentage of total action repre- 
sented by each of the two agencies. 
III. In the case of (3), (4), or (5), is the area to be mapped as 
landslide or moraine ? 
It is to be noted in regard to the points named above that as 
regards I, 1, it is highly probable that in strict literalness there is no 
morainal deposit anywhere which has not subsequently been sub- 
ject in some degree to a settling and shifting of its materials, and if 
the deposits have had steep slopes some of these movements would 
no doubt deserve the name of landsliding; the same thing must 
necessarily be true of morainal deposits laid down on steep slopes 
of underlying material of whatever nature, or on any slope which 
is made up of materials which are themselves creeping, slumping, or 
sliding; but in many cases the amount of readjustment of material 
has evidently been so small that the effects due to landsliding may 
be disregarded. As to point III above, the question of representa- 
tion on an areal map may sometimes be difficult to decide. It 
would seem that on a general areal map that agency should be 
represented which has clearly had the larger share in the transpor- 
tation of the material at or near the surface; this necessarily means 
that agency which has most recently accomplished a notable 
amount of transportation of materials at or near the surface. Ona 
map drawn to show especially glacial phenomena, even a small 
percentage of glacial débris may properly determine the inclusion of 
the area within the glaciated tract. Another method combining 
both of the above, used on the areal sheet of the Engineer Mountain 
Folio, is at times very desirable, especially in the case of valleys 
where the drift is in general small in amount, viz., to indicate the 
upper limit of glaciation by a definite line, and within the glaciated 
area to map moraines, landslides, bed rock, etc., as the character of 
the surface in the respective cases may warrant. 
On the map (see Part I) the purpose has been to show clearly 
the maximum extent of glaciation in the recent epoch, and conse- 
quently no account has been taken of the fact that at some points 
within the areas indicated the débris has been notably readjusted 
in position by creeping, slumping, or sliding; this is especially true 
