Brady and Crosskey — Notes on Fossil Ostracoda. 61 



clays to resemble very closely those of some similar formations in Scot- 

 land, and less closely those of dredgings obtained in the seas around 

 the Hebrides and Shetland. 



The character of the Mollusca with which the Ostracoda are 

 associated justifies the same observation. About two-thirds of the 

 Mollusca collected from the Scotch glacial clays are also found in 

 the corresponding beds of Canada ; and the difference between the 

 glacial fossil fauna of Canada and that now existing in the Gulf of 

 St. Lawrence is far less marked than the difference between the 

 glacial fauna of the Clyde beds and that now existing in the Firth. 

 The fossil fauna of Canada is slightly more arctic than that of the 

 Gulf, but does not contrast with it so broadly as the fauna of the 

 Scotch glacial clays with the Mollusca still living in the neighbour- 

 ing waters. The resemblance between the fossil glacial Ostracoda 

 of America and the Ostracoda of Scotch glacial clays, being closer 

 than the resemblance between the glacial and the living Ostracoda 

 of Scotland, renders the determination of their relationship to living 

 American Ostracoda of considerable geological importance. It may 

 be useful to geologists to enumerate the Ostracoda found in the 

 various clays we have examined, and indicate at the same time the 

 general character of the groups of Mollusca with which they are 

 associated. 



Portland. — Out of 31 species of Mollusca catalogued, 18 occur 

 fossil in Scotch glacial clays, including such characteristic forms as 

 Pecten GroenlandicxiiS; Pecten Islmidicus ; Leda pygmcea ; TelUna cal- 

 carea (^proxima) ; Natica affinis {clausa) ; Buccmiim Groenlandicum. 

 The associated Ostracoda are : 



Cytherura Sarsii (Brady). 



„ cristata, nov. sp. 



„ striata (Sars). 



„ granulosa, nov. sp. 



„ undata, var. 

 Cytheropteron latissimum (Norman). 



„ nodosum (Brady). 

 Sclerochilus contortus (Norman). 

 Faradoxostoma variabile (Baird). 



Cy there einarginata (Sars). 



„ concwma (Jones). 



„ Bawsoni (Brady). 



,, limicola (Norman). 



„ dunelmensis (Norman). 

 Cytheridea papillosa (Bosquet). 



,, Sorbyana (Jones). 

 Loxoconcha granulata (Sars). 

 'Xestoleheris depres&a (Sars). 

 Cytherura nigrescens (Baird). 



Saco (Maine). — On the banks of the Saco river, about ten miles 

 from its mouth, 15 species of Mollusca are catalogued, of which only 

 five occur in the Scotch clays, viz. : Leda pxjgmoBa ; Leda arctica ; 

 Nucula inflata ; Menestho alhida ; Natica affinis — M. alhida, however, 

 being rather doubtful and very young. The great abundance of 

 Leda arctica constitutes a remarkable analogy between this bed and 

 the clay at Errol near Dundee, and at Moss in Christianiafjord. 

 The associated Ostracoda are : 



Cy there leioderma (Norman). 

 lutea (MuUer). 

 MacChesneyi, nov. sp. 

 emnrginata (Sars). 

 limicola (Norman). 

 cuspidata, nov. sp. 

 dunelmensis (Norman). 



Cytheridea papillosa (Bosquet). 



„ cornea (Brady and Robertson). 



,, Sorbyana (Jones). 



„ WiUiamsoniana ? (Bosquet). 

 Cytheropteron latissimum (Norman). 



„ complanatum, nov. sp. 



