Triassic wood from the Malay states
W.N. Edwards, a palaeobotanist at the British Museum (Natural History), published this concise note in 1933 describing two fossil coniferous woods from the Malay States, both assigned to the form-genus Dadoxylon. The paper’s central thesis is that the identification of one specimen as Dadoxylon sclerosum Walton—a species previously documented only from South Africa and Kenya—establishes a biogeographic connection between the Malay Peninsula and the African continent during the Upper Triassic, extending the known geographic range of that taxon and reinforcing earlier evidence of a northern-type Permo-Carboniferous flora in the region.
Summary
The article reports on two silicified and pyritised fossil wood specimens presented to the British Museum by J.B. Scrivenor, late Director of the Federated Malay States Geological Survey. The first, from a rubber estate at Jerantut in Pahang, is a substantial log preserving pith, primary xylem, and secondary xylem; the second, from the Ulu Nenggeri River in Kelantan, consists of dense black secondary wood without pith or primary xylem, partially replaced by pyrites. Scrivenor assigned both to the Triassic on stratigraphic grounds, and Edwards’ microscopical examination was undertaken to test and refine that age determination through anatomical comparison with known Dadoxylon species from other parts of the world.
The analytical core of the paper is a detailed anatomical comparison of the Jerantut specimen with Walton’s (1925) South African type of D. sclerosum and Williams’ (1930) Kenyan material. Edwards notes that the presence of small thick-walled cell groups in the pith region—comparable to the sclereids Walton described—is the critical diagnostic feature linking the three localities, even though the preservation in the Malay specimen is imperfect and no longitudinal section passed through those groups. Two minor differences (the near-absence of growth rings and the predominantly uniseriate bordered pits in the Malay wood) are judged not to warrant specific separation, particularly given that Williams reached the same conclusion for the Kenyan material. The Kelantan specimen, by contrast, differs sufficiently from the Jerantut wood in tracheid diameter, ray height, and pitting pattern to preclude conspecificity, but lacks distinctive enough features to justify a new name.
In the concluding section Edwards places the finding within a broader biogeographic framework. He recalls his own 1926 record of Pecopteris and Cordaites from the Raub series of Kelantan, which indicated a northern-type Permo-Carboniferous flora in Malaya related to that of Sumatra, and notes Lightfoot’s (Walton 1929) discovery of pecopterids associated with Glossopteris in Rhodesia, which opened the question of whether northern types penetrated southern Gondwanaland via the East Indies and Malaya. The D. sclerosum record, while not resolving that Permo-Carboniferous question, does indicate a clear Upper Triassic affinity with East and South Africa. Edwards also observes that the feeble or absent growth rings in the Malayan and Kenyan specimens, contrasted with the strongly marked rings in the South African wood, may reflect differing climatic conditions across the range.
Key Findings
- The D. sclerosum specimen from Jerantut, Pahang, is a silicified log approximately 32 cm in diameter and 22 cm in height, found by E.S. Willbourn on a rubber estate and weathered from arenaceous beds overlying andesite (p. 236).
- The pith shows an apparent diameter of 1–2 cm due to a mass of chalcedonic quartz radiating into cracks, but microscopical examination suggests the true pith diameter was probably at most a few millimetres (p. 236).
- Tracheids in the Pahang specimen measure about 50 μ in diameter; rays are uniseriate, 1–20 cells in height, with tangential cell width of 20–35 μ (p. 236).
- The Kelantan Dadoxylon sp. has tracheids up to 70 μ in diameter, rays 1–40 cells high with tangential width usually less than 20 μ, and bordered pits in 1–4 rows (usually 2 or 3) (p. 237).
- The South African type of D. sclerosum (Walton 1925) is from the top of the Molteno beds, which Du Toit referred to the Upper Triassic; the Kenyan material (Williams 1930) is from the Mazeras Sandstone, an upper member of the Duruma Sandstone underlying lower Jurassic beds (p. 237).
- Growth rings are distinctly marked in the South African wood, almost completely absent in the Kenyan material, and faint or absent in the Malay specimen—a pattern Edwards suggests may reflect differing climatic conditions (pp. 237, 240).
Conclusion
Edwards’ definitive takeaway is that the microscopical characters of the Jerantut wood confirm Scrivenor’s stratigraphic age estimate of Triassic and, more specifically, point to an Upper Triassic horizon. The identification of D. sclerosum in Malaya extends the known range of that species from southern and eastern Africa to the Malay Peninsula, indicating a biogeographic relationship with East and South Africa during that period and adding to the sparse but growing record of plant fossils from the Malay States.
Context
- The specimens are held in the British Museum (Natural History) collection; the Kelantan material is catalogued as B.M.N.H. no. V. 21465e (p. 238).
- The paper contributes to the early palaeobotanical record of the Malay Peninsula, building on Edwards’ own 1926 Pecopteris and Cordaites record and Scrivenor’s 1931 Geology of Malaya, and situates Malayan Triassic floras within the broader Gondwanan biogeographic framework then under active investigation.