403 
NOTES ON SOME JURASSIC SHELLS FROM BORNEO, INCLUDING 
A NEW SPECIES OF TRIGONIA. 
By R. Burren Newron, F.G.S., etc. 
Read 12th June, 19038. 
PLATE XVI. 
Tnx Jurassic rocks of Borneo appear to be restricted to the western 
part of the island, and chiefly to that area known as the Sultanate 
of Sambas; they occur also in certain parts of the country of the 
Sarawak river, and in some west central localities lying among the 
upper reaches of the river Kapuas. Only the first two districts 
have yielded molluscan remains, the third forming the area wherein 
Dr. G. A. F. Molengraaff discovered siliceous organic rocks containing 
Radiolaria, which were described some few years since by Dr. G. J. 
Hinde! as of probably Jurassic age (= Danau formation or pre- 
Cretaceous of Molengraaff).? 
Mr. C. J. van Schelle, a mining engineer, first collected Jurassic 
shells in the Sepang and Mottong districts of Western Borneo, 
although Professor K. Martin, in describing their characters during 
1890, mistook them for specimens of probably Cretaceous age; they 
comprised two forms of Gervillia and a Corbula. Subsequently, with 
more information at his command, Martin was able to regard these 
fossils as of Lias age, on account of their association with Ammonites 
resembling Harpoceras radians. 
Professor Martin next called attention to Jurassic mollusca obtained 
by Mr. Wing Easton and Dr. Bosscha from various localities of 
Sambas, including the genera Corbula, Protocardia, Evxelissa, etc., 
as well as some Ammonite remains identified as Perisphinctes. He 
was in favour of regarding this fauna as of Jurassic age, since the 
Cephalopod was more particularly represented in the ‘Malm’ of 
Europe and in the Indian Jurassic Series. 
This same group of shells was afterwards described by Dr. F. Vogel 
as belonging to the ‘Brauner’ or ‘ Weisser Jura’ period, although 
he was inclined to think that the later age was the more correct one. 
During the same collecting expedition molluscan remains were 
found which proved to be of older date than those just referred to, 
on account of the presence of Ammonites allied to Harpoceras radians, 
a characteristic Cephalopod of the Upper Lias formation, these speci- 
mens being described and figured at the time by Dr. P. G. Krause. 
1 G. J. Hinde: ‘‘ Description of Fossil Radiolaria from the Rocks of Central Borneo, 
obtained by Professor G. A. F. Molengraaff in the Dutch Exploring Expedition 
of 1893-1894 ”’ ; Leyden, 1899. 
2 G. A. F. Molengraaff: ‘‘ Borneo-Expeditie: Geologische Verkenningstochten in 
Central- Borneo (1893-1894) ’’?; Leyden and Amsterdam, 1900. Ibid., English 
translation, published 1902. 
