187 



Gresslya peregt'ina occurs, according to Fox-Strangwats'), 

 in the Blea Wyke beds, the Grey Limestone (Humphriesianum- 

 zone) and the Cornbrash of the Lower OoUte, in the Kellaways 

 Rock, the Lower Calcareous Grit and Lower Limestone, the 

 Middle Calcareous Grit and Upper Limestone of the Middle Oolite 

 of Yorkshire. Woodward^) quotes it from the Inferior Oolite 

 (Muchisonae-zone), the Fuller's Earth, Clay and Rock, questionably 

 from the Great Oolite, the Stonesfield Slate, the Cornbrash 

 (Macrocephalus-zone) , the Kellaways Rock (Calloviense-zone) 

 and the Corallian (Plicatilis-zone) from Dorsetshire to Yorkshire. 



Pleuromya. Agassiz. 

 ? Pleuromya sp. 



P]. VI, fig. 17. 



A cast in light-coloured sandstone, which may possibly 

 have been derived from a species of Pleuromya, was found by 

 0. Nordenskjold in a block. This block was found in Aucella 

 River in the south-west of Jameson's Land, below the spot 

 where the Aucella-sandstone crops out. 



Unfortunately the state of preservation of the cast does not 

 allow of accurate determination. 



Pholadomya Sowerby. 

 Pholadomya angustata. Sowerbt. sp. 



PI. VI, fig. 20. 



1823. Lutraria angustata. Sowerby, J. Mineral Conchology of Great Bri- 

 tain, vol. 4, p. 29, tab. 327. 



1874. MoESCH, С Monographie der Pholadomyen. Abh. Schweiz, palæont. 

 Ges. Basel und Genf. vol. 1, p. 33, tab. X, fig. 2, 3, 4. 



A fairly well-preserved cast of a Pholadomya, in fine-grained 

 brown sandstone has been obtained from Mount Nathorst. This 

 corresponds fairly well with Moesch's description of Pholadomya 

 angustata, yet an appreciable distinction is seen in the fact 



') Fox-Strangwats, C. 1892, p. 162 and 217. 



2) Woodward, H. B. 1894, p. 561, and 1895, p. 375. 



