20 JOHAN KI^ER. [SEC. ARCT. EXP. FRAM 



1. The fossiliferous conglomerates and sandstones of Skrap Valley in 

 the middle part of the series. 



2. S. 0. Haken's sandstone probably higher up in the series, although 

 the precise distance cannot be stated. 



3. The dark schists of Galge point, somewhat higher. 



4. The conglomerate strata at Bregnekleften, just above the preceding. 



Lamellibranchiata. 



Phtonia cf. cylindricci HALL. 



(PI. II, figs I 2). 



Amongst the specimens collected by PER SCHEI in the rich fish 

 horizon at Skrap Valley we find an abundance of a small mussle which 

 is of considerable interest. 



As regards the determination of the genus, this is no easy matter, 

 as I have only this species and no material for the purpose of compa- 

 rison. At first I was inclined to favour the genus Glossites; but the 

 absence of a Innula in the new form, the less pointed anterior end, and 

 the almost straight cardinal line, seem to separate this specimen from 

 the latter. Modiomorpha, which was also posible, has a more oblique 

 form. At the same time it appears to agree very well with HALL'S 

 description of the genus Phtonia 



]) e s c r i p t i o n. The shell is small, elongate-elliptical the length 

 being a little more than twice the height. The basal margin is straight 

 or slightly convex. Posterior extremity regularly rounded, but somewhat 

 oblique on the upper posterior margin. Anterior end short, narrowed, 

 and rounded or somewhat pointed at the extremity. Cardinal line nearly 

 straight, about half the length of the shell. Valves moderately convex. 

 Beaks subanterior. low, appressed, with sometimes a faint indication of 

 a depression extending from the beak to the basal margin. 



Surface marked by fine, even, concentric striae: radiating striae are 

 not to be seen. As a rule a few coarser lines of growth are visible. 

 Anterior muscular scar distinct, posterior muscular scar obscure. 



Three specimens measure respectively 16, 17.5 and 17.5 mm. in 

 lenght and 7.5, 7.5 and 8 mm. in height. 



Observations. This description has been kept close to that of 

 Phtonia cylindrica HALL as given by HALL 1 , and agrees almost enti- 

 rely with the same. Doubt may be occasioned by one or two points. 



1 Nat. Hist, of N. York. Palaeontology. Vol. V. I. Lamellibranchiata, II, 1885, pag. 473. 



