498 SMUIDSES IHRE SIMGIDIEIN IOS 
confirm the evidence drawn from the meanders of the Seine as 
to the two-cycle, composite topography of the region. Sheets 
It and 32 include the extremities of this interesting and excep- 
tional deformation. The trend of its anticline carries it north- 
west towards the Isle of Wight, and suggests its association with 
the sharp upturn by which the Chalk is revealed on the southern 
side of that island. 
The upland on either side of the Seine exhibits the features 
of adolescent dissection in the most characteristic form. The 
digitate valleys, although narrow and steep-sided, have well- 
graded floors. Much uncut upland still remains between the 
headwaters of the streams, yet the form and arrangement of the 
valleys immediately suggests the active headwater extension of 
every little branch. Some of the roads and railways follow the 
chief valleys; others traverse the upland, systematically avoid- 
ing the valley heads ; still others ascend one branch valley, cross 
the upland and descend another valley. The larger cities are 
in the chief valleys; but the upland has many villages and is 
very generally occupied. The steeper valley sides are commonly 
forested. 
The lower course of the Seine is now entered by strong tides, 
as if the region had suffered a slight depression since the exca- 
vation of the valley. The flood tide enters the estuary as a bore 
or mascaret, best seen at Caudebec, about midway between 
Havre and Rouen. The tidal scour seems here to have greatly 
aided the normal action of the river in widening its valley floor. 
While the convex lobes of the upland that enter the meander 
curves above Rouen still retain their normal form and allow only 
a narrow flood plain to the river, those that enter the valley 
further down-stream are in many cases reduced to acuminate or 
blunt cusps; the production of these cusps by the gradual con- 
sumption of the original lobes being clearly indicated by the 
transitional forms seen in regular order on passing down the 
valley, and by the manner in which the cusps point into great 
concave amphitheaters on the opposite side of the valley. Three 
examples of this kind about Quillebouef are beautifully shown. 
