THE GLACIAL DEPOSITS OF NORTHERN PEMBROKESHIRE. 73 
Cyprina islandica, L. . : : : ; 5 ‘ : F common, 
Tellina (Macoma) balthica, i : ‘ : 5 : : : moderately rare. 
Mactra (Spisula) solida, L. . : : : ; : ‘ : 5 rare. 
Venus (Ventricola) casina, L. F : 3 : ; : : 4 moderately rare. 
Tapes (Amygdala) decussatus? L. , : ‘ ‘ , d 3 very rare. 
Cardium islandicum ? Chem. ; : ; : : - : very rare. 
Mya truncata, L. . ; é ; : ; 3 : : c rare, 
ScaPHOPODA. 
Dentalium entalis? L. . : ; : ; , ‘ ; é rare. 
GASTEROPODA. 
Puncturella noachina, L. , : é ; : ; ' very rare. 
Natica clausa% Brod. aud Sow. . ‘ : ; 3 : : é rare, 
Turritella communis, Lam. . ; ; ; : : : common. 
Buccinum undatum, L. : ; : : ; , : : : common. 
Tritonofusus gracilis, Da Costa ; : : : F : ‘ very rare. 
Ocinebra erinacea, L.  . ; : ‘ : : : : very rare. 
Trophon (Boreotrophon) danni Ee : 4 : - : F common. 
a scalariformis, Gould f : ‘ moderately rare. 
Nase (Hima) incrassata, Strom. . c : : : : very rare. 
Bela turricula, Mont. . . . : : ; : : rare. 
Bela rufa, Mont. (elongate a) : : ; : : 2 rare. 
Fragments of other shells were also found, but they were too broken for identifica- 
tion. Some of the shell fragments found were very thick, especially pieces of Cyprina 
aslandica. Many are rolled, and the majority very broken. Entire single valves of 
Astarte compressa were found; and of the univalve shells, Ocinebra erinacea and 
Trophon clathratus occurred in nearly perfect condition. 
The fauna appears to contain a mixture of species belonging to different climates : 
Astarte borealis, Trophon clathratus, and Trophon scalariformis are Arctic and 
Scandinavian species, not now found living in British seas. 
Astarte compressa, Cyprina islandica, Buccinum undatum, and Puncturella 
noachina belong to a northern type of British species which inhabit Arctic and 
Scandinavian seas in common with our own. 
The shells are in very much the same condition as those which have been obtained 
at Moel Tryfan and at Gloppa, and most of the forms found at Manorowen occur in 
the other two places also. But Nuculana, which occurs rarely at Manorowen, is 
common at both of the other places. 
Pectunculus glycimeris is abundant at Manorowen, but very rare at Moel Tryfan 
and Gloppa. Venus casina, though frequent at Manorowen, is also rare at the 
other places. 
Samples of the sand from several places were examined microscopically, and they 
all showed a very close resemblance to marine sands. Most of the grains were of 
