《太平广记·卷四百六十五·水族二》
蠔就是牡蛎，初时生在海岛边，像拳头大的石头，从四面渐渐地生长，有的长得高一二丈，象高大险峻的山。
蠔即牡蛎也，其初生海岛边，如拳石，四面渐长。
Oysters, initially found on the edges of islands, are fist-sized rocks that gradually grow from all sides, some growing to be one or two zhang tall like high, precipitous mountains.
<s>[INST] Identify the key themes in this Classical Chinese text and explain them in English: 蠔即牡蛎也，其初生海岛边，如拳石，四面渐长。 [/INST] Oysters, initially found on the edges of islands, are fist-sized rocks that gradually grow from all sides, some growing to be one or two zhang tall like high, precipitous mountains.</s>
Identify the key themes in this Classical Chinese text and explain them in English: 蠔即牡蛎也，其初生海岛边，如拳石，四面渐长。
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Oysters, initially found on the edges of islands, are fist-sized rocks that gradually grow from all sides, some growing to be one or two zhang tall like high, precipitous mountains.
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