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SUPPLEMENT TO THE CRAG MOLLUSCA. 



Note B. — The ten species from Walton are the following, viz. Nassa conglobata, African; N. granu- 

 lata, Japanese ; Actmon Etheridgii, which Mr. Jeffreys speaks of as identical with a species (exilis) from the 

 Atlantic abyss ; Trophon costifer, from the same abyss ; Scalara subulata, which Mr. Jeffreys mentions 

 from Teneriffe ; Gastrana laminosa, South African ; Cardita scalaris, Pacific ; Mactra deaurata, which 

 seems to me to be M. Jauresii of the United States Coast ; and Buccinum glaciale and Solen gladiolus, 

 which are Arctic. 



Note C. — The twenty-two species from the Red Crag other than Walton are the following, viz. 

 Nassa granulata, Japanese ; Gastrana laminosa, South African ; Trochus multigranus, reported by Mr. 

 Jeffreys from the Atlantic and from the Scandinavian Coast ; Trophon costifer, from the Atlantic abyss ; 

 Cardita scalaris, Pacific ; Nassa propinqua {trivittata ? Say), Pleurotoma bicarinata, Cardium pinnatulum, 

 and Mactra deaurata (J£ Jauresii), from the coast of the United States ; and Buccinum glaciale, Trophon 

 Sarsii, T. scalariformis, Pleurotoma pyramidalis, P. violacea, Cancellaria viridula, Amaura Candida, Natica 

 occlusa, Leda lauceolata, L. oblongoides (L. Arctica ? Gray), Cardium Grcenlandicum, Tellina lata, and 

 Solen gladiolus, which are Arctic. 



Note D. — The twelve species from the Fluvio-marine Crag are the following, viz. Cardita scalaris, 

 Pacific ; Pleurotoma bicarinata, United States Coast ; Trophon Costifer, from the Atlantic abyss ; and 

 Pleurotoma pyramidalis, Cancellaria viridula, Velutina undata, Leda lanceolata, L. oblongoides (i. 

 Arctica ? Gray), L. myalis, Cardium Grcenlandicum, Astarte borealis, and Tellina lata, which are 

 Arctic. 



Note E. — The nine species from the Chillesford beds are the following -.—Cardita scalaris, Pacific ; 

 Corbula contractu, United States Coast; and Natica occlusa, Margarita argentata, Leda lanceolata, L. 

 oblongoides (L. Arctica ? Gray), Cardium Grcenlandicum, Astarte borealis, and Tellina lata, which are 

 Arctic. 



Note F. — The four Lower Glacial species are — Leda oblongoides (Z. Arctica 1 Gray), L. myalis, 

 Astarte borealis, and Tellina lata, all of them Arctic. 



Note G.— The ten Middle Glacial species are the following, viz. Nassa granulata, Japanese ; Cardita 

 scalaris, Pacific ; Corbula conlracta, United States Coast ; and Trophon scalariformis, Leda lanceolata, 

 L. oblongoides (L. Arctica 1 Gray), Cardium Islandicum, Astarte borealis, Venus fluctuosa, and Tellina lata, 

 which are Arctic. 



Note H. — The twenty-three Upper Glacial species are, Columbella Holbollii, Trophon Sabini, T. 

 ventricosus, T. craticulatus, T. scalariformis, T. Gunneri, Pleurotoma elegantior (P. elegans ? Moll.), 

 P. pyramidalis, P. scala?-is, Trichotropis insignis, Turritella erosa, Natica occlusa, Margarita elegantissima, 

 Pecten Islandicus, Leda caudata, L. pernula, L. oblongoides {L. Arctica? Gray), Cardita borealis, Cardium 

 Islandicum, Astarte borealis, A. crebicostata, Venus fluctuosa, and Tellina lata, all of them Arctic. 



Note I. — The four Post-glacial species are, Trophon scalariformis, Pleurotoma pyramidalis, Astarte 

 borealis, and Tellina lata, all of them Arctic. 



The results of the table indicate an almost identical percentage of forms not known 

 as living in the case of the older Red Crag and the Coralline, which is in conflict with the 

 geological break, which I still believe to exist between the two formations. With the 



