The Botany of Iceland - 01.12.1914, Page 25

The Botany of Iceland - 01.12.1914, Page 25
PHYSICAL GEOGRAPHY 209 insula, and Skogafoss and Seljalandsfoss below Eyjaíjallajökull. Tliese cascades have a height oi' about 100 metres and more. The largest rivers, only, have been mentioned above, but in addition to these, hundreds of streams of greater or lesser ATolume occur, often with beautiful waterfalls and cascades in connection with picturesque clefts and rocks. As mentioned above, the torrential and changeable glacier-rivers have a destructive influence upon the cultivation and vegetation of the plains. The greensward is torn off and large areas are covered by gravel, therefore the level country south of Vatnajökull is in several places turned into a desert almost destitute of vegetation except where special natural conditions afford a shelter from the destructive effect of the rivers. Where the action of the glacier-rivers is suddenly arrested hy any natural phenomenon the level country again becomes quickly covered with plants. As an example may be mentioned the fact that Hverfisfljót, in the year 1783, was forced out of ils hed by a great lava-stream, and a considerable stretch of land — Brunasandur — which had previously been irrigated by cold and torrential river-branches Avas freed from these, only a few clear streams of filtered glacier-water with a slight current issuing from the edge of the lava-streams and flowing down the level country; so that where in 1783 there Avas a gravelly and sandy flat withóut plant-life and without means of sustenance for huinan beings there is now a parish with seven farmsteads and abundance of meadows and pasture-lands for the sheep and cattle of the in- habitants. In itself the glacier-water is not inimical to vegetation; it is only tlie torrential current, the changeableness of the water- courses, and the low temperature of the water which have a de- structive effect upon plant-growth; where tliese factors are not active, the glacier-water, with its contents of fine clay, is on the contrary a fertilizer; therefore in the neighbourhood of the mouths of the largest glacier-rivers, where there is only a slight current and the water has become warm on the way, fertile tracts of meadows are often found where the glacier-water is profitably utilized for irriga- tion. Water from rivers such as Thjórsá and Hvítá has, by analysis, been proved to contain an unusually large quantit\r of alkali and phosphoric acid. Lakes. There are many lakes in Iceland, but the majority of them are of sinall size. The largest lakes — Thingvallavatn and
Page 1
Page 2
Page 3
Page 4
Page 5
Page 6
Page 7
Page 8
Page 9
Page 10
Page 11
Page 12
Page 13
Page 14
Page 15
Page 16
Page 17
Page 18
Page 19
Page 20
Page 21
Page 22
Page 23
Page 24
Page 25
Page 26
Page 27
Page 28
Page 29
Page 30
Page 31
Page 32
Page 33
Page 34
Page 35
Page 36
Page 37
Page 38
Page 39
Page 40
Page 41
Page 42
Page 43
Page 44
Page 45
Page 46
Page 47
Page 48
Page 49
Page 50
Page 51
Page 52
Page 53
Page 54
Page 55
Page 56
Page 57
Page 58
Page 59
Page 60
Page 61
Page 62
Page 63
Page 64
Page 65
Page 66
Page 67
Page 68
Page 69
Page 70
Page 71
Page 72
Page 73
Page 74
Page 75
Page 76
Page 77
Page 78
Page 79
Page 80
Page 81
Page 82
Page 83
Page 84
Page 85
Page 86
Page 87
Page 88
Page 89
Page 90
Page 91
Page 92
Page 93
Page 94
Page 95
Page 96
Page 97
Page 98
Page 99
Page 100
Page 101
Page 102
Page 103
Page 104
Page 105
Page 106
Page 107
Page 108
Page 109
Page 110
Page 111
Page 112
Page 113
Page 114
Page 115
Page 116
Page 117
Page 118
Page 119
Page 120
Page 121
Page 122
Page 123
Page 124
Page 125
Page 126
Page 127
Page 128
Page 129
Page 130
Page 131
Page 132
Page 133
Page 134
Page 135
Page 136
Page 137
Page 138
Page 139
Page 140
Page 141
Page 142
Page 143
Page 144
Page 145
Page 146
Page 147
Page 148
Page 149
Page 150
Page 151
Page 152
Page 153
Page 154
Page 155
Page 156
Page 157
Page 158
Page 159
Page 160
Page 161
Page 162

x

The Botany of Iceland

Direct Links

If you want to link to this newspaper/magazine, please use these links:

Link to this newspaper/magazine: The Botany of Iceland
https://timarit.is/publication/1834

Link to this issue:

Link to this page:

Link to this article:

Please do not link directly to images or PDFs on Timarit.is as such URLs may change without warning. Please use the URLs provided above for linking to the website.