Fossils of the Dufton Shales.
Actinozoa.
1. Petraia, sp. Swindale.
2. Chætctes, sp. An incrusting, subniassive species, commonly growing on Orthocerata. Thin sections show that the tubes are furnished with a few remote tabulæ. Surface characters unknown. Common at Pusgill along with Discina corona, Salt., sp., Bellerophon bilobatus, Sow., &c.
Annelida.
1. Conchicolites gregarius, Nich. This singular form is found abundantly along with the incrusting species of Chætetes just spoken of, attached to the outer surface of Orthocerata, in the Discina-corona bed.
Brachiopoda.
1. Leptæna transversalis, Wahl. Smelt Mill, Hilton.
2. Strophomena expansa, Sow. Harthwaite Gill, Dufton.
3. Leptæna sericea, Sow. A small variety of this shell with fewer principal radii than the normal form, and of about half its size, occurs very abundantly in Pusgill, and less commonly in all the other localities.
4. Orthis testudinaria, Dalm. Swindale and Pusgill.
5. Discina (Trematis) corona, Salt. This fine Brachiopod occurs abundantly, though in a more or less fragmentary condition, in a single stratum in Pusgill, along with Orthocerata, Conchicolites gregarius, Bellerophon bilobatus, &c.
6. Lingula tennigranulata, M'Coy. Pusgill.
7. ovata, M'Coy. Pusgill. Both these Lingulæ seem to be confined to the stratum with Discina corona.
8. Orthis biforata, Schloth. Dufton-Town dykes.
9. Strophomena rhomboidalis, Wilckens. Pusgill.
10. Orthis vespertilio, Sow. Dufton-Town dykes.
Heteropoda.
1. Bellerophon bilobatus, Sow. Pusgill.
Cephalopoda.
1. Orthoceras, sp. A smooth form resembling O. baculiferme, M'Coy. Common at Pusgill, in the Discina-corona stratum.
2. Oncoceras, sp. Not uncommon at Pusgill, in the same bed as the preceding.
Crustacea.
1. Calymene Blumenbachii, Brongn. Very abundant in Pusgill and Dufton-Town dykes, less so in Swindale.
2. Trinucleus concentricus, Eaton. Very abundant in Pusgill and Dufton-Town dykes, less abundant in Swindale.
3. Cybele verrucosa, Dalm. Dufton-Town dyke.
4. Ampyx nudus, Murch. (?) Rare in Pusgill.
5. Lichas laxatus, M'Coy. Pusgill.
6. Illænus Bowmanni, Salt. Swindale and Hilton.
7. Encrinurus, sp. Pusgill.
8. Beyrichia Wilckensiana, Jones. Abundant in Pusgill in the Discina-corona bed, and also in the ashy beds in Swindale.
9. Primitia semicircularis, Jones & Holl. In ashy beds. Swindale.
The predominance in the Dufton Shales of such Brachiopods as Strophomena expansa, Leptæna sericea, Orthis testudinaria, O. vespertilio, O. biforata, and Lingula ovalis, together with the abundance of such trilobites as Calymene Blumenhachii, Trinucleus concentricus,
