8 
Frank Carney 
nounced re-entrant angles; the drift would have a correspondingly 
even front, while it might have a very irregular surface. This 
type of topography is apt also to impose its characteristics upon 
the drift itself, as may be seen in the prairie regions. (2) In a 
section where the major valleys approach a position transverse 
to the general direction of ice-movement, the drift is found massed 
in these valleys, especially on their iceward sides; while in the 
Fig. 2. An east-west section showing contact of the two drifts as exposed 
south of Dunning’s Landing. The wavy, irregular line marks the upper surface 
of the blue till. 
tributaries of these major valleys are moraine loops or dams. 
(3) If, however, the chief valleys approach a position parallel to 
the general direction of ice-movement, we find in them lateral i 
moraines^^ blending into loops of drift in the bottoms of the valleys ; 
while the secondary valleys may be partially clogged or buried 
with drift. 
R. S. Tarr, Bulletin of the Geological Society of America, vol. xvi, pp. 218, 219. 
