128 Canadian Record of Science. 



Supplement to Acadian Geology, last edition, (as Naiadites) ; 

 Salter, Journal of Geological Society, last edition ; Acadian 

 Geology, second edition, p. 205 ; Wheelton Hind, Journal of 

 Geological Society, 1. c. 



This is small, broad-ovate, the small umbo about one-third 

 of the distance from the anterior end of the straight hinge- 

 line. To the naked eye the younger shells seem almost 

 circular. The shell is very thin and the epidermis smooth 

 and shining, and much wrinkled in flattened specimens. 

 This litlle shell has been found in only one bed, a black 

 shale in the lower part of the Joggins coal-measures near 

 the upper part of the millstone grit. It resembles A. Scotica 

 of Great Britain. 



3. Anthracomya arenacea, Dawson. 

 10 



Fig. 10. — Anthracomya arenacea, Upper Coal-formation, Pictou, 

 enlarged x 2. 



Supplement to Acadian Geology, last edition ; Salter, Journal of 

 Geological Society, second edition, p. 205 ; Wheelton Hind, 

 Journal of Geological Society, 1. c. 



Shell elliptical, smooth or with very fine concentric lines. 

 Epidermis thin, in many specimens absent. More than 

 twice as long as wide. Anterior margin narrowed in front 

 of beak. Beaks about one-sixth of the length from the an- 

 terior end. Posterior end somewhat narrowed at extremity. 



This species is usually found in gray arenaceous beds of 

 the upper coal-formation and the millstone grit. It is com- 

 paratively rare in the middle coal-formation. 



All our museum specimens are from Pictou and Sydney. 

 The species may be compared with A. lanceolata of Great 

 Britain. 



