ENG-1955 — Page 257

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HONG KONG ANNUAL REPORT

the whole region within recent geological times. Progressive uplift has brought about marked changes on the shore-line. Submerged weathered rock surfaces overlain by peat and bog deposits drilled through in the harbour of Hong Kong indicate that the former shore-line was at least 100 feet (16 fathoms) lower than now.

During the period of submergence valley heads were gradually filled with sediment, and this has been redistributed from higher to lower levels as elevation continued. The paddy fields along the lower reaches of the rivers, and the large semi-submerged plain around Yuen Long are alluvial deposits brought down by local streams. At the brickyards on the Sheung Shui plain marine shells have been dug up fifteen feet below the alluvial deposits.

The alluvial origin of the plains is thus clear, and it is also evident that these plains are yearly growing seaward, due to the deposition of sediment brought down by streams. It is interesting to note that an elevation of the land by 100 feet would restore the strand line approximately to the 16 fathom line, and make all Hong Kong and the New Territories an integral part of the mainland. Thus, across wide alluvial plains, the Pearl River would develop several distributaries to the sea. There would possibly be a small channel flowing between Hong Kong and Lantao Island eastwards, and a larger one passing close to the western end of Lantao in a south-easterly direction.

FLORA

It is not possible to make any true distinction between the trees of the Colony and those of the adjacent southern part of Kwangtung Province. Among the principal trees found in Hong Kong and the New Territories are pine, Chinese banyan, and camphor, to which, since the area came under British administration, have been added a large number of others, of which the most commonly seen are casuarina, eucalyptus and flamboyant.

The principal locally-grown fruits include laichee, lung- ngan, wong pei, loquat, pomelo, tangerine, banana, papaya, pineapple, custard apple, guava, and Chinese varieties of plum and pear. Of these, papaya, pineapple, custard apple and guava were originally introduced from South America by the Portuguese some time after the foundation of Macau. The