Page:Quarterly Journal of the Geological Society of London, vol. 33.djvu/209

Rh AX0 CIRQUES EN XOKWAI AND GKEENLAM).

17L

with .special reference to these ; this theory elucidates the whole. The moraines, which are terminal, indicate the limit to which the the glacier has advanced daring some period of the Glacial epoch ; the lakes occur along this line because they have been made by the glaciers.

The occurrence of these lakes behind the moraines is so regular that many years ago Professor Keilhau, who had no idea that the banks in front of them were moraines, or their basins formed by glaciers, expressly stated that this regularity was too marked to be accidental. The above relation between lakes and rows of moraines is repeated several times in Xorway. Different rows of moraines and lakes there belong to different extensions of the glaciers : for example, from 30 to 40 kilometres to the north of the aforesaid first row of lakes there is, near the town of Drobak, another series of lakes and moraines. Further to the north is found a third series ; but the largest lakes in Xorway occur in the fourth row, which includes the lakes of ITjosen, Eandsfjord, Spirillen, Kroderen, and Soneren. In front of these lakes, which are situated in valleys, the loose detritus takes the form of terraces, like those mentioned above in front of the lakes in the fjord-valleys of Western Xorway.

The heights and depths of the above lakes are given in the follow- ing Table : —

Xame of the lake.

©

©

M

©

M

c3

c3

©

i— »

© [>

A

a

pC o

-t-i

■*-> ■— i

Cm O

"is

o

-U 02

fcD

cS

fcC >

H

©

©

<1

i— 1 c3

kilo- metres.

kilo- metres.

metres.

99

364

121

73

131

132

25

35

151

39

38

132

10

7

118

© M

O

g §

c -5

©

o ©

^ ©

±> © ©

"©.5 a

Mjosen .... Randsfjord Spirillen. Kroderen. Soneren

metres.

452

108

108

31

40

metres. 195 200 200 190

When the first-mentioned row of moraines and lakes was formed the ice-masses were yet continuous. For this reason the configura- tion of the country here is without strongly marked valleys, and the moraine is, on the whole, continuous. When the last row of large lakes was formed, the ice-sheet had separated itself into distinct glaciers, owing to which the detritus in front of the lake cannot be followed from the end of one lake to another.

From these observations it results that about fifty lakes or rock- basins, among which are some of the largest in Xorway, have mo-