GASTEROPODA. 23 



convex volutions, which are encircled with six regular striations ; the aperture is ovate, the 

 base somewhat flattened and smooth ; there is no umbilical depression. 



A small shell, with the last volution expanded and depressed ; the striations are rendered 

 slightly scabrous by very delicate, obtuse, decussating ornamentation, partially preserved, 

 and which is only visible under a considerable magnifying power. 



Geological Position and Locality. The Great Oolite of Minchinhampton Common, 

 collected by Mr. Witchell. 



MONODONTA COMPOS JTA, Lt/c. Tab. XLV, fig. 6. 



Testa parva subdepressa, spira anfractibus 3 4 angustis, angulatis, superne concavis ; 

 lineis angustis, regularibw subdistantibus cingendis, anfractu ultimo permagno, superne 

 costulis dcpressis longitudinalibus lineis decmsatis; aperturd magnd ovatd, columella 

 solida, dentata. 



Shell small, rather depressed; spire with the volutions (3 4), angulated in their 

 middle part, narrow, delicate, and rather distantly arranged, the last volution is very large ; 

 the surface above the mesial keel is concave, and has closely arranged, depressed, longitu- 

 dinal, little elevations or ribs, which are rendered nodulous in their upper parts by the 

 encircling lines ; the aperture is moderately large ; the columella has a conspicuous 

 thickening at its base ; there is also a slight umbilical depression. 



Geological Position and Locality. The Great Oolite of Minchinhampton Common, 

 collected by Mr. Witchell. 



SOLARIUM BATHONICUM, Lye. Tab. XLV, figs. 27, 27 a, 27 b, 27 c. 



Testa parva depresaa, superne planata, inferne concavo, concentrice striato ; anfractibus 

 (3) anyustis fabuJatis, externe subcarinatis nodulisque paucis, obscuris, coronatis ; lateribus 

 subconvexis striatis. 



Shell small, depressed, flattened above, concave beneath and concentrically striated ; 

 volutions (3) narrow, tabulated, externally slightly carinated, and with a few obscure 

 coronary tubercles; the upper and lateral surfaces have encircling striations, the sides 

 being slightly convex. 



The specimen examined has a diameter of only two lines, the height being equal to 

 about one third of the breadth. 



Geological Position and Locality. The upper beds of the Great Oolite in the vicinity 

 of Bath, collected by Charles Moore, Esq. 



