42 Notices of Memoirs — 



Leda clara. Geol. Mag. 1874, Decade II. Vol. I. PL XVII. Fig. 1. 



Subelliptical, lanceolate, nearly equilateral, somewhat but not 

 extremely rostrated. Disk smooth, shining ; valves with a few fine 

 close regular concentric riblets perceptible near the anterior angle, 

 where an indistinct sulcus runs upwards towards the umbo. No 

 distinct escutcheon. Lunule narrow, indistinctly defined. Umbones 

 prominent. Ventral margin slightly angulated at about a third of 

 its length from the posterior point, where an obscure carina runs 

 to the margin from the umbo. Length 12 mill., height 6, thickness 

 about 4 mm. Miocene, Jamaica. 



In shape somewhat like L. nasuta. It is rather difficult to describe 



the smooth plain species of this genus ; their differences being most 



generally noticeable in shape, extent of rostrum, etc. The following 



species have been already described from West Indian Tertiaries : — 



Leda PacTceri, Forbes, Eocene, Barbados. 



„ incognita, Guppy, Eocene, Trinidad. 



,, bisuleata, Guppy, Upper Miocene, Jamaica. 



„ illecta, Guppy, Pliocene, Trinidad. 



,, perlepida, Guppy, Pliocene, Trinidad. 

 Three species of Nucula have been recorded from the same 

 formations. 



Litrupa dentalinum. Geol. Mag. 1874, Decade II. Vol. I. PI. XVI. 



Eig. 11. 



Tube clavate, curved, slightly irregular in diameter, gradually 

 increasing from the smaller end, which is annulate, becoming smooth 

 towards the middle of the shell ; the lower half smooth, shining, 

 rather suddenly thickened near the aperture, to form which it as 

 suddenly contracts to a diameter not greater than that of the smaller 

 third of the tube. 



There are no very distinct characters by which to separate this 

 annelid case from D. planum of the European Eocene. I have thought 

 it as well, nevertheless, to indicate its presence in the Jamaican 

 Tertiaries under a provisional name. 



Crassinella. 



I have proposed this name in substitution for that of Gouldia, pre- 

 occupied for a genus of birds. The typical species are Cr. pacifica 

 and Cr. martinicensis ; the latter occurs in the Pliocene of Trinidad. 



1TOTICBS OIE 1 MEMOIES. 



" Sub, la Correlation des Formations Cambriennes de la 

 Belgiqtje et du Pats de Galles." By Prof. G. Dewalque. 

 (From the Bulletins of the Royal Academy of Belgium, 2nd 

 series, torn, xxxvii. no. 5, May, 1874.) Translated by G. A. 

 Lebour, F.G.S. 



AFTER an excursion to Wales in the autumn of 1872, which I 

 undertook in order to study the petrographical characters oi 

 the oldest formations of that region, I announced to the Academy 



