402 THE CANADIAN NATURALIST. [Vol. viii. 



River porphyrite, which may belong to the same species. These 

 are strikingly like Syncyclonema 3Ieekiana, from the Queen 

 Charlotte Islands, in the condition in which that fossil is most 

 commonly obtained, but the exterior of the test of the convex 

 valve of S. Meehiana is known to be both closely and nodosely 

 cancellated. 



4. Lima duplicata, Sowerby (Sp). Two left valves of a Lima 

 both from Sigutlat Lake, which if not identical with the Plagios- 

 toma duplicata of the " Mineral Conchology," are remarkably like 

 it in shape, and so far as can be ascertained at present, in sculpture 

 also. One specimen has the test partly exfoliated ; in the other 

 the shell is considerably decomposed, but its original surface 

 markings are sharply impressed on part of the rock which was 

 broken from the specimen, and which originally enveloped most 

 of one side of it. The sculpture consists apparently of about 

 twenty-eight acute, angular, radiating costse, each of which al- 

 ternates with a single, fine, raised line, just as in L. duplicata. 



In the Quarterly Journal of the Geological Society of London 

 for 1866 (Vol. XXII., p. 82) Mr. Tawney has described a species 

 with very similiar shape and style of ornamentation, from the 

 Lower Lias of South Wales, under the name Lima subduplicata. 

 Mr. Charles Moore, however, in a paper on " Abnormal Second- 

 ary Deposits," published in the Journal of the same Society for 

 the following year, places L. subduplicata as a synonym of L. 

 duplicata on page 509, though on page 530 of the same paper 

 it is said to be identical with L. dentata Terquem, which is ad- 

 mitted to be distinct from L. duplicata. It may be, therefore, 

 that more than one species have been confounded under this 

 name, but if not, few if any Mesozoic molluscs have a wider 

 range in time than L. duplicata. Originally described from 

 the Coralline Oolite of Yorkshire, it is abundant in the Corn- 

 brash, Forest Marble, Great and Inferior Oolite of many parts 

 of England, as the writer can testify from direct observations in 

 the field. Munster says it is found in the Lias of Germany 

 associated with Rhynchonella rimom, and Goldfuss mentions it 

 as occurring in the Inferior Oolite of Hanover and Brunswick. 

 It is included by Rev. P. B. Brodie in a list of Lower Lias 

 fossils from near Wells, (Somerset), also by Mr. C. Moore, in 

 lists of species from the same formation in South Wales, and 

 from several localities in Somersetshire in the zone of Ammonites 

 Bucklandi. 



