繁體中文
《香港地質導賞書》第 7 章記載：香港嘅石炭紀岩石屬新田群——下部係元朗組嘅碳酸鹽岩，現已變質成大理岩，喺香港境內冇出露，全靠鑽孔證明（元朗、天水圍一帶同大嶼山北面離岸都有）；上部係落馬洲組嘅非碳酸鹽沉積岩，喺新界北部（大石磨、河上鄉一帶）大面積出露，亦見於屯門谷地東側，沉積環境屬近岸潮灘或三角洲沖積平原，大嶼山以北嘅大小磨刀島出露嘅石墨質粉砂岩同石墨片岩屬落馬洲組米埔段。元朗組大理岩可溶，溶蝕形成溶洞，對該區樓宇基礎設計同施工有重要影響。同樣係官方一手文獻嘅里程碑，唔屬志錄抽取層；時間標籤照來源只寫紀名。
English
Chapter 7 of the Hong Kong Geology Guide Book records that Hong Kong’s Carboniferous rocks belong to the San Tin Group: the lower Yuen Long Formation consists of carbonate rocks, now metamorphosed to marble, which are nowhere exposed in Hong Kong and have been proved entirely by drillholes (under Yuen Long and Tin Shui Wai and offshore north of Lantau); the overlying Lok Ma Chau Formation consists of non-carbonate sedimentary rocks exposed over a large area of the northern New Territories (around Tai Shek Mo and Ho Sheung Heung) and along the eastern side of the Tuen Mun valley, deposited in a near-shore tidal flat or on a deltaic alluvial plain, with the graphite-bearing siltstone and graphitic schist of The Brothers islands north of Lantau belonging to its Mai Po Member. The Yuen Long Formation marble is soluble, and the resulting solution cavities have had important consequences for foundation design and construction in the area. This is likewise an official primary-source milestone outside the extracted archive layer; the time label reproduces the source and names the period only.
出處：《香港地質導賞書》第 7 章「變質沉積岩——落馬洲組」（印刷頁 46–50，含元朗組未有出露、全靠鑽孔證明同溶洞影響嘅記述）。Provenance: Hong Kong Geology Guide Book, chapter 7, “Metasedimentary Rocks – Lok Ma Chau Formation” (printed pp. 46–50, including the account of the Yuen Long Formation never being exposed, being proved entirely by drillholes, and the solution-cavity consequences).