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of the district. Ma Wan near Tsing Yi, has a sizeable village which is expected to expand greatlyas a result of employment at the new airport.Other sizeable islands in the district include Hei Ling Chau, Shek Kvvu Chau and Tai A Chau.All are sites for government institutions and have restricted public access. Of the smaller islandssurrounding Lantau, only Tai Mo To (West Brother) in the north, Chau Kung To (SunshineIsland) in the southeast, and Siu A Chau in the southwest have supported small, temporarypopulations. During the preparation of this memoir, The Brothers islands were largely obliteratedas part of the new airport development on Chek Lap Kok. Tai 0, which is separated from thebody of Lantau Island by a narrow tidal channel, is considered to be part of Lantau.Previous WorkThe earliest geological survey of the Territory was undertaken between 1923 and 1927 by Brock,Uglow, Schofield and Williams, under an agreement between the Colonial Office and theUniversity of British Columbia. A map was published at 1:84480 scale (Brock et aL, 1936)\vhich showed JLantau to be composed L qf the^ possibly Upper Jurassic, Jtepulse Bay Volcanicsjnd Tai Mo Shan Porphyries, with outcrops of Cretaceous Lan Tau Porphyritic Granite in thenortheast. Cretaceous Hong Kong Granite was shown as the dominant rocktype on the smallerislands, while The Brothers islands and Tai O area were ascribed to the possibly Lower Jurassic,Pan^ Sin Sediments of the Tolo Channel Series. Unfortunately, no descriptive memoir wasproduced to accompany this map, but several related publications (Uglow, 1926; Brock &Schofield, 1926; Williams, 1943; Williams et aL, 1945) presented many of the main conclusionsrelated to the mapping. A book, based largely on this earlier work, was written by Davis (1952),which was followed by a detailed description of the geology of the Territory by Ruxton (1960).A systematic survey of the Territory by geologists from the Institute of Geological Sciences,United Kingdom, resulted in the publication of two, 1:50 000 scale geological maps and anaccompanying memoir (Allen & Stephens, 1971). These were the best references to the geologyof the district prior to the remapping described here, which began in 1986. The GeotechnicalArea Study Programme (GASP), initiated by the Geotechnical Control Office in 1979 (Brand eta/., 1982), produced 1:20 000 scale engineering geology and other maps for the Territory as awhole. The geology on these maps drew extensively on the work of Allen & Stephens (1971), butincluded new interpretations of superficial deposits and photolineaments.Bennett (1984b) made a comprehensive review of the stratigraphy of Hong Kong and the SouthChina region. He also reviewed the superficial deposits and weathering of the Territory (1984a),and its tectonic history, structure and metamorphism (1984c).In the neighbouring Sha Tin district (Sheet 7), Addison (1986) established a detailedlithostratigraphy for the Repulse Bay Volcanic Group, and divided the granites using lithologicalcriteria. His volcanic lithostratigraphy was modified in the adjoining Kowloon and Hong KongIsland district to the south (Strange & Shaw, 1986), and in the western New Territories(Langford et aL, 1989), and has now been extended, in its modified form, into parts of thisdistrict. The division of granite intrusions in the district is based on the classification of Strange(1984).Palaeontological studies of plant-bearing strata (Nau & Wu, 1991; Lee et aL, 1990) haveresulted in differing interpretations of the age of the volcanic rocks of Lantau. These ages span arange from late early Jurassic to early Cretaceous.Before the early 1980s, publications on the geology of Hong Kong (Davis, 1952; Allen &Stephens, 1971; Bennett, 1984a) only briefly covered the offshore geology of the Territory,concentrating on sediments in the littoral and sublittoral zones. Investigations of the geotechnical17