THE
CHINESE REPOSITORY.
VOL. X.-AUGUST, 1841.- No. 8.
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ART. I. Notices of Chusan: its geological formation; climate; productions; agriculture; commerce and capabilities; people, &c. In continuation of the article on Chusan in the June number, a few remarks on the geology of the island and coast, extracted from the Calcutta Journal of Natural History, may not be uninteresting. The article in that Journal was written by lieutenant Ouchterlony, Madras engineers.
“The prevailing rock of the island belongs to the ancient volcanic class, and comprises many varieties, but principally clay-stone, clay- stone porphyry, felspar, compact and porphyritic, and trachyte.
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In portions of the cliffs on the south and north coasts, the rocks are observed to assume a columnar structure, and dykes and masses of greenstone burst through the beds of clay-stone on various points, in- durating and altering them to a considerable extent, On the west coast, the clay-stone porphyry assumes a slaty or laminated structure, and appears to be quarried extensively both for use on the island and for exportation to the main land, affording excellent slabs for paving and for floors, and good blocks for common building purposes. A coarse conglomerate is also to be seen, intervening between beds of the claystone, imbedding angular fragments of many descriptions of igneous rocks, and passing into a compact and workable porphyry, which is also quarried and made use of for pillars, blocks for corn mills, basement slabs, &c., &c. The very best materials for road- making and repairing are readily procurable in most parts of the island; and for buildings of any descriptions in the sea-port town of Tinghar, such as barracks, warehouses, docks &c., stone could be
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