NEWTON : ON BORNEAN JURASSIC SHELLS. 405 
Lias. Oo.LiTE. 
Corbula Eastoni, Vogel... ae ss ae wwe 4 
Corbula sp. indet. ... ae ae iste oe ne * 
Cucullea sp. es oe ee * 
Cuspidaria (Neera]) Sambasana, Vogel a be seis * 
Gervillia Borneensis, Martin ses Lis Be aoe * 
Gervillia sp indet. ... “ee ate me a 
Inoceramus sp. BEA BO soe sia * 
Mytilus Sambasanus, Vogel : 
Pholadomya ck. multicostata, Agassiz 
Protocardia crassicostata, Vogel 
Protocardia multiformis, Vogel 
Protocardia tenuicostata, Vogel 
Pseudomonotis sp. 
Pteroperna sp. 
Trigonia Molengraafi (sp. nov.) 
Volsella { = Modiola] sp. : a ; 
Attention may now be dhicoted to a amrell collection of Jurassic 
shells obtained by Mr. Edward T. McCarthy from Buduk (= Boedoek) 
in the Dutch territory of Western Borneo, which he presented to the 
British Museum (Natural History) during 1897. The specimens 
vary in mineralization, having been found in some altered clay-beds 
of the old Chinese gold-mines, and comprise Gastropod and Lamelli- 
branch remains associated with coniferous wood and impressions of 
erioidal stem fragments. From their occurrence in a soft ferruginous 
red-clay deposit the tests of the majority of the shells are converted 
into a kind of brown iron-ore or limonite; these particular specimens 
being collected at about 50 feet below the original surface. Some 
further material consists of numerous casts of small bivalves, Zrigonia, 
etc., crowded together and forming nodular or spherical masses of 
a grey-coloured cindery-looking rock. 
Molluscan remains (Euspira and Protocardia) are also observable in 
a greyish-black, compact, siliceo-calcareous matrix (weathering almost 
white), heavily charged with iron pyrites, and exhibiting a small 
percentage of gold, which came from a depth of 89 feet. At a similar 
depth from the surface a hard reddish clay rock was obtained, 
showing indeterminable shell fragments (Zwspira), which, among 
other minerals, according to Mr. McCarthy, also contains gold to the 
amount of 2 dwts. per ton. This little collection, besides being 
illustrative of species described by Dr. Vogel in 1896 and 1900, 
includes the genus Zrigonia, which is now recorded for the first time 
from the Jurassic rocks of Borneo. 
1. Triconra Motencraarri, n.sp. (Pl. XVI, Figs. 1-6.) 
Shell small, ovately trigonal, moderately convex, and of nearly 
equal height and length; anterior border rounded, posterior end 
truncated; umbones almost mesial, obtuse, slightly recurved; area 
depressed, covered with closely- set transverse striations divided by 
a feeble though distinct median furrow; marginal carina gently 
curving and slightly raised, the inner carina shorter ; escutcheon 
narrow and of small dimensions ; surface ornamented with con- 
centrically excavated, step-like costa, equally spaced, and elevated; 
intercostal areas furnished with numerous perpendicular clavate ridges 
bearing oblique striations. 
* 
