Page:Quarterly Journal of the Geological Society of London, vol. 25.djvu/219

 but in general, throughout the east and north-east of Kwangtung and the greater portion of Fuhkien, igneous and metamorphic rocks form the most conspicuous geological feature of the country. The

Fig. 4. — Part Section of Si Tungting-shan. (Scale 4 miles to 1 inch.)

1. Grits and Shales, No. 3.           4. Quartzose Shales, probably No. 5. 2. Limestone with Chert-nodules, No. 4. 5. Limestone, No. 6. 3. Alluvial deposits.

granites of the coast-chain and of some inland districts, of Kwangtung and Kiangsi especially, give a forbidding aspect to the scenery where they occur. From the large amount of mica they contain, as well as from the excess of alkaline materials of the felspar, they are readily decomposed, and have yielded to the disintegrating action of the atmosphere (in these regions saturated with water for a large portion of the year) to an enormous extent, leaving behind a mass of soft unctuous clay surrounding the grains of unaltered quartz. The granite, however, is very concretionary in its structure and irregular in character ; and here and there are to be seen large masses of solid stone, which have resisted decomposition and lie like enormous boulders imbedded in the surrounding matrix. In places exposed to the wear and tear of the tropical rains this matrix has been washed away ; and the undecomposed masses left far and wide over the surfaces of the hills have more than once been referred to as the results of glacial action, corresponding with the boulder drift of more northern latitudes*. In many localities this decomposed rock, annually washed by the rains, assumes a most barren aspect, giving a blank and desolate appearance to the coast of the southern provinces as seen from the sea, deep channels worn by the mountain-torrents, and detached masses of every form scattered about, giving the whole an air of utter confusion. At Amoy especially may this be noticed, where the whole coast seaward presents a mass of white sandy hills glaring in a subtropical sun, and only relieved by the black of the detached boulders which he around.

Granite, however, is not the only plutonic rock to be met with. In Kwangtung and Fuhkien large masses of porphyry of many varieties are found ; trachytes containing a large portion of free silica are likewise abundant, as also large masses of greenstone. In Fuhkien large quantities of rock apparently felspar are found, of a fine grain and greenish colour, which form admirable building-stones. In Kiangsu and the Yangtse provinces granites and trachytes seem to form the characteristic igneous rocks.


 * See Ansted's ' Elementary Course of Geology,' 2nd Edit. p. 42.