GASTEROPODA. 99 



Testa cylindricd, spirdparvd sub-inversd, apice mammillato ; anfractibus angustis jolanis ; 

 anfractu ultimo margine rotunddto. 



Shell cylindrical ; spire small, somewhat inversed in the latter volutions ; apex mam- 

 millated ; volutions narrow, flattened ; the last one rounded at the upper margin. 



The upper margin of the last whorl rises as high as the one or two preceding ones, 

 leaving their edges exposed so that the small mammillated apex and one or two first 

 whorls seem to rise from a cavity. In the character of its spire this shell forms a passage 

 to the remaining species, in none of which does the apex of the spire rise higher than the 

 margin of the last whorl, the vertex is consequently more or less bowl-shaped or concave, 

 the volutions never being entirely concealed, but exhibiting their upper edges. 



This is a rare shell, and, with the preceding species, is found indifferently in all the 

 beds of shelly oolite belonging to this Formation. 



Locality. Minchinhampton Common ; Ancliff, Wiltshire ; Langrune, France. 



Cylindrites angulatus. PL VIII, fig. 11, 11 a, b. 



Testa cylindricd; spird mediocriter elatd, sub-concavd ; apice acuto ; anfractibus (8) 

 angustis superne angulatis. 



Shell cylindrical ; spire moderately elevated, with rather concave sides, and an acute 

 apex ; volutions eight, narrow and angular in their upper part. 



The general figure of this shell is somewhat shorter than C. acutus, the volutions are 

 very narrow and angular, which, together with the somewhat concave spire, give it a well- 

 marked form ; it is more common than the last species. 



Locality. The upper beds of the Great Oolite near Minchinhampton. 



Cylindrites altus. Plate VIII, figs. 12, 12a, b. 



C. Testa cylindricd, subfusiformi, spird elatd; anfractibus (8) planis latis. 



A cylindrical, subfusiform shell, with an elevated spire, and eight flattened, and rather 

 broad, volutions. 



In this species the spire is flattened with an acute apex, which is equal in length to a 

 third portion of the entire shell. 



Locality, Minchinhampton Common. It is moderately rare. 



