. The botany of Iceland. Botany -- Iceland. 244 THORODDSEN there upon the highest ridges and peaks, which cannot be reached bv the coarser grains of the drifting sand, are seen small patches of soil supporting mosses and a few phanerogams. In Iceland blown sand consists almost invariably of decomposed volcanic rocks; quartz-sand does not occur in Iceland. The most common blown sand is palagonite-dust usually of a yellowish-brown colour, which when examined microscopically, is seen to consist of glass-particles, tachylite, palagonite, plagioclase, augite and various. Fig. 15. Mohella in Kroksda
. The botany of Iceland. Botany -- Iceland. 244 THORODDSEN there upon the highest ridges and peaks, which cannot be reached bv the coarser grains of the drifting sand, are seen small patches of soil supporting mosses and a few phanerogams. In Iceland blown sand consists almost invariably of decomposed volcanic rocks; quartz-sand does not occur in Iceland. The most common blown sand is palagonite-dust usually of a yellowish-brown colour, which when examined microscopically, is seen to consist of glass-particles, tachylite, palagonite, plagioclase, augite and various. Fig. 15. Mohella in Kroksdalur, not far from Sandmiiladalsa, (Phot. Heinrich Erkes.) finely decomposed zeolitic alteration-products. Volcanic ashes of recent date often occur as blown sand especially in the interior of the lava-wastes; they are heavier and less mobile, consequently, they are not dispersed in quantities beyond the volcanic districts. In the neighbourhood of the great glacier-bearing mountains, considerable tracts of level land are often covered with glacial clay, which when dried, crumbles into dust and drifts beyond the nearer surroundings. Around Dyngjufjoll, especially south-east of Askja, large areas are covered with blown sand, consisting of liparitic pumice-dust which all dates from the eruption of 1875. Moreover, stretches of blown sand consisting of decomposed mussel shells, i. e. calcareous dust, occur here and there along the coast of the north-western Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Kolderup Rosenvinge, L. (Lauritz), 1858-1939; Warming, Eugenius, 1841-1924. Copenhagen, J. Frimodt
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Keywords: ., bookcentury1900, bookcollectionbiod, bookdecade1910, bookyear1912
