VALLEYS. 193 
so on; and the river issues from the other end clear and 
ees, ready to resume its levelling labours lower 
own. 
‘By such a process of deposition are these wide valleys 
gradually filled up, and then the river flows gently in a 
long winding course through the rich territory of its own 
depositing, like an old man calmly enjoying the fruits of 
his early. toil, and contemplating the good deeds of his 
youth ; for the youthful river, in the brawling early days 
of its mountain life, is doing good servise to the world 
in thus converting desolation into fertility. Nearly all the 
fertile plains of the earth have been created thus by the 
industry of rivers. 
‘Besides these there is seen yet another kind of valley, 
partaking of the characters of both of the above: a long 
trough-like valley formed by the mountain sides, but which 
widens as it-proceeds downwards, and branches into the 
great valley of the sea. The waters of the sea fill its lower 
part, and an estuary, firth, or fiord is formed. These in like 
manner are continually being filled up by the rivers which 
come to rest in the waters of the sea, and deposit their 
burdens there. Thus has Holland; the master-piece and 
last labour of the Rhine, been formed. 
_ ‘The Gula, into whose valley I now descend, presents some 
illustrations of these river agencies, and a problem to boot. 
The mounds and knolls that appeared so complex from 
above are seen from below to be formed by the river cut- 
ting its way through the alluvium it has deposited, This 
may have been effected in two ways ; the deposit may have 
been made in a lake filling a basin-shaped valley, and the 
river may have cut down and lowered the channel of its 
outlet considerably beyond its original depth, and thus have 
not only drained the waters of the lake, but have given suffi- - 
cient inclination and velocity to the river to enable it to 
carry with it much of the soft earthy matter over which it 
was flowing; or it may be that this was an estuary valley, 
an ancient fiord, up which the sea stretched an arm, the 
alluvium being deposited by the river when it entered the 
ca) 
