Prof. Mi Ine — Across Europe and Asia. 
467 
Name of River. 
N. Lat. 
Ice Forms. 
f Sir Daria, near Aral. 
45° 0' 
Nov. 20 
Basin of 
the Obi. < 
Obi, near Barnaul. 
53° 14' 
Oct. 30 
Tobol, near Kurgan. 
55° 32' 
Oct. 26 
Irtish, near Tobolsk. 
58° 20' 
Oct. 24 
Obi, near Obdorsk. 
67° 28' 
Oct. 20 
Basin 
Angara, near Irkutsk. 
52° 20' 
Dec. 30 
of the ' Lake Baikal.* 
Yenisei. ( Yenisei, near Krasnoiarsk. 
53 J 0' 
Dec. 23 
56° 6’ 
Oct. 29 
Basin of 
Lena, near Kirensk. 
57° 40' 
Oct. 25 
the Lena. 
Lena, near Yakutsk. 
Gl° 58' 
Oct. 21 
Basin of 
the Yana. 
Yana, near Ust Yansk. 
71° 23' 
Sept. 6 
Ice breaks up. 
March 22. 
April 15. 
April 15. 
April 20. 
May 20. 
May 20. 
April 20 — May 10. 
April 20. 
April 30. 
May 13. 
May 24. 
* Lake Baikal, which is introduced amongst the table of rivers, like tke rapid 
Angara which flows from it, is very irregulär in its time of freezing and in opening. 
These times also vary in different parts of the lake, as migkt be espected from its 
north and south extension. 
is that on the same river, the northern portion of the river freezes 
only a little earlier than the Southern part, whilst it, comparatively 
speaking, breaks up a considerable time later. Thus, for instance, 
on the Obi, at Obdorsk, near its mouth, the ice only forms about one 
week before it does at Barnaul, which is a considerable distance to 
the south, whilst it breaks up a montli later. 
For Illustration, suppose we take the Biver Nile near its mouth, 
and partially reduce the area of its channel with a blockade of ice 
for a week : I think we might reasonably expect a flood. Floods of 
this kind may be observed in low latitudes, as on the Angara near 
Irkutsk. In 1870, a sudden frosfc rapidly freezing the river over, a 
flood was caused which did great damage to the town. But this is 
not the worst aspect of the action which may be illustrated by taking 
the Nile, not at an ordinary seasou, but at the time when it is drain- 
ing off an unusually large quantity of water from the south, and at 
such a time placing a barrier across its mouth, not for one week, but 
for three or four. The consequences would be, I think, disastrous. 
It will be observed that it is at these times when the Siberian rivers 
have the most water, from the melting of the Southern ice and snow, to 
drain away, that their mouths are for the longest period dammed up. 
Düring past times, when the cold was probably more intense, these 
barriers of ice may have been more continuous and complete, and 
thus have kept the plains — which were then smaller than they are at 
present, because their northern ends were beneath the sea — more or 
less constantly covered with a lake of turbid water. As this flood 
varied in its nature, being more or less dependent upon the accuruu- 
lation and breaking up of the ice, so we had beds of a varying 
nature deposited; sometimes they were of silt, and sometimes they 
were of sand. 
And in this way, whilst accepting the main feature in Mr. Belt’s 
argument that it was a barrier of ice which caused a freshwater 
lake, I should endeavour to explain the origin of the Siberian 
Steppes, without seeking the aid of a Polar Ice Cap. 
We have now a Palseocrystic Ice Cap upon our northern hemi- 
