THE ANNALS 



MAGAZINE OF NATURAL HISTORY. 



No. 58. JUNE 1842. 



XXXI. — General Features of Chusan, with remarks on the 

 Flora and Fauna of that Island. By Theodore Cantor, 

 M.D., Bengal Medical Service, &c. 



The island of Chusan, or Great Chusan, is situated on the 

 east coast of China, between lat. 30° and 31° N. and long. 122° 

 and 123° E.* It is the greatest and most important of the 

 group of islands which bear that name, and is separated from 

 the nearest main-land, Keeto Point, by an arm of the sea, 

 about ten miles across, thickly studded with smaller islands, 

 varying in extent from little slightly elevated rocks to islands 

 several miles in circumference. This uninterrupted chain of 

 islands renders it necessary to look upon Chusan, and the 

 whole group indeed, more as a part of the continent than as 

 islands. The extremes of temperature are more like those of 

 a continent than of an island. The aspect of Chusan is hilly, 

 being traversed by steep rocks in all directions, occasionally 

 surmounted by peaks with intervening valleys. The rocks 

 belong to the older volcanic series, chiefly consisting of clay- 

 stone, porphyry, and a number of varieties, of which Lieut. 

 Ouchterlony in his statistical notes has given the following 

 description : — 



ee In portions of the cliffs on the south and north coasts the 

 rocks are observed to assume a columnar structure f, and 

 dykes and masses of greenstone burst through the beds of 

 claystone on various points, indurating and altering them to 

 a considerable extent. On the w r est coast the claystone pofr- 



* An observatory erected in 1840 near the engineer camp was situated 

 in .30° 0' 10" N. and 122° 14' E. The variation of compass was found to be 

 2-33 E., magnetic dip 42*16. The circumference of the island is 51| miles ; 

 its greatest length about 20, its greatest breadth 10| miles. The direction 

 of the island is from N.W. to S.E. 



f Columnar structure is also visible on Buffalo Island, a short distance 

 to the southward of Chusan. 



Ann. $ Mag. N. Hist. Vol.ix.' T 



