276 BURTON : THE STORY OF THE LINCOLN GAP. 
ork ; and, as this went on year after year, and the valley was pushed 
back further to the south, the Trent was reached at last, and tappe 
near Newark ; perhaps, as Mr. Jukes-Browne suggests, ‘on the occasion 
of some great flood, when the last intervening barrier gave way.’ 
Whether this is correct or not—and something of the kind may 
have easily occurred—I cannot doubt that, for a very long time 
afterwards, the two opposing channels struggled for the supremacy, 
and that the river flowed both ways; but, as the Humber continued 
deepening its bed, and, as a consequence, deepening and pushing 
back its ‘longitudinal’ valley also, while the land between Newark 
and Lincoln, where the old channel ran, was reduced almost to 
a level, the result was inevitable; the captured Trent gave way at 
last to the yielding marls of the Keuper, and—no longer a ‘ primary’ 
but a ‘subsequent’ stream—became a tributary of the Humber. 
This is but a mere outline of the subject, and those who wish to 
know more of it should read Mr. Jukes-Browne’s paper ; and also an 
article in the magazine of the Royal Geographical Society, of last 
February, by William Morris Davis, Professor of Physical Geography, 
Harvard University, ‘On the Development of certain English Rivers,’ 
which deals with the subject more fully and elaborately than has 
been attempted by any previous author. A careful perusal of this 
most able and instructive paper will well repay the reader for his 
trouble. 
After the Trent was captured, it would no doubt, for a long time, 
have a tendency to resort to its original course in times of 
flood. The Triassic and Rhcetic escarpment, which now bounds it 
on the East, is a very weak one at the best; and only here and there, 
in places like Gate Burton, Gainsborough, and Burton Stather, does 
it present anything like a formidable barrier; while, in many parts, it 
is a mere bank, and scarcely that; but, as years went on, and its new 
channel through the soft Keuper marls was deepened, this tendene 
would gradually diminish. 
The Trent has always been liable to floods. Before its course a 
was changed the narrowness of the Lincoln outlet prevented any 
rush of water getting away quickly; and the wide extent of groun 
covered by gravel deposits between Newark and Lincoln shows how 
greatly aes land around was flooded. 
t that distant period also, a powerful tributary, which has 
left its ane on the land in the shape of an ancient gravel- -bed, 
entered the Trent near Lincoln, adding to the difficulty. 
This stream, according to Mr. Jukes-Browne, had its source 
among the hills near Belvoir Castle, where the small river Devon, its : 
modern representative, now rises. 
a 
