244 PROCEEDINGS COTTESWOLD CLUB 191 1 



GERVILLIA FORNICATA Lycett. PL xxviii., fig. 3. 



T.d. 1857. " The Cotteswold Hills," p. 121. 



T.f. [None given by Lycett. Type-figure PI. xxvill., fig. 3]. 



T.l.^ " Nailsworth, Gloucestershire." 



H. " Upper Lias." [Toarcian] 



yj. [variabilis] 



Colin. Mus. Pract. Geol., Jermyn Street, London. [25183]. 



Type-description. — " Shell ovate, hinge line straight, oblique, lengthened; 

 umbones acute, elevated, anterior auricle short, sloping somewhat downwards, 

 dorsal surface very much elevated, and narrow, lines of growth numerous and 

 faintly marked ; antero-inferior border slightly sinuated ; hinge plate narrow, 

 sulcations numerous, irregular. The right or more flattened valve is unknown. 



" Gervillia glabrata, Koch and Dunker [Versteinerungen des Norddeut- 

 schen Oolithgebildes, 1837, pp. 27-28, tab. II., fig. i], approximates to this 

 species in figure, but that shell is more elongated, less convex, has a shorter 

 hinge line, and much larger folds of growth. It is rare. 



" Position. — The CynocephalaStAge:. 



" Locality. — Buckholt Wood." 



Remarks. — This species is remarkable for the great con- 

 vexity of the left valve. 



Lycett did not figure any example of this species, nor did 

 he mark any specimen as being that upon which he based his 

 description. In the original description, he gives the horizon 

 of his species as the " Cynocephala-StSige " and the locality as 

 " Buckholt Wood " {vide supra). But there is no specimen 

 in the Lycett Collection at the Museum of Practical Geology, 

 Jermyn Street, from this horizon at this locality. There are, 

 however, two specimens from Nailsworth which were originally 

 in Lycett's possession. On p. 25 of his book " The Cotteswold 

 Hills," he records this species from the " Basement Bed of the 

 Cynocephala-Stdige " at Nailsworth. This bed, which in the 

 words of Lycett, " is a brown or chocolate coloured argillaceous 

 sandstone," occurs a few feet above the base of the Cotteswold 

 Sands, and Mr Richardson thinks is of about variabilis hemera." 



So the matter stands thus : the proterotype came from the 

 Cephalopod-Bed (probably that portion which is of moorei 

 date) of Buckholt Wood, but cannot now be found. It is 

 described on p. 121 of Lycett's " Cotteswold Hills " Two 

 specimens (idiotypes) are in the Museum of Practical Geology 

 [25182, 25183] which were recorded on page 25 of the same 



1 Lycett's type cannot be found, therefore details are given concerning the lectotype. 



2 Proc. Cottesw. Nat. F.C., vol. xvii., pt. i (1910), p. 127- 



