926 DR F. R. C. REED ON THE 



Davidson, but it somewhat suggests an alliance with Camarella Thomsoni and 

 C. balclatchiensis ; the more elongated and narrower shape of the shell and strong 

 continuous plications help to distinguish it. The ornamentation also is a notice- 

 able feature, well seen in the Balclatchie examples. The true generic reference is 

 uncertain. It is named after the famous geologist of last century, J. J. Conybeare. 



Camarella ? cuneatella (Davidson). 



(Plate XXII, figs. 25, 26.) 



1883. Rhynchonella cuneatella, Davidson, Mon. Brit. Foss. Brack., vol. v, Silur. Suppl., p. 200, 

 pi. x, fig. 11. 



In this shell the long sloping flattened shoulders with false areas and the general 

 shape resemble Rhynch. ardmillanensis (see p. 941), but the folds are coarser, 

 fewer, and only marginal ; the beak of the pedicle-valve also seems lower. In 

 Davidson's poor type-specimen from the Balclatchie conglomerate there are five 

 plications on the brachial valve, and they do not curve outwards on each side as 

 Davidson incorrectly shows. In other specimens from the same locality (mounted 

 and named by Davidson with the type) there are 5 or 6 folds on the brachial 

 valve, the 2 middle ones being usually rather larger and closer, and on the pedicle- 

 valve there are 3-4 on each side of the shallow narrow sinus. 



There are many poorly preserved small shells from Craighead which may be a 

 variety of this species, but the marginal plications are usually 6 or 7, and there is no 

 median sinus or fold, the front edge being straight. A shell compared with this 

 species has been described by the author # from the Glensaul Limestone, Co. Galway. 



Horizons. — (l) Balclatchie Group ; (2) Stinchar Limestone Group ? 



Localities. — (l) Balclatchie (conglom.), Ardmillan ; (2) Craighead. 



Camarella Peachi (Davidson). 



(Plate XXII, figs. 27, 28.) 



1883. Rhynchonella Peachi, Davidson, Mon. Brit. Foss. Brack., vol. v, Silur. Suppl., p. 201, 

 pi. xi, fig. 25. 



This species has been sufficiently described by Davidson, but he was misled in 

 thinking that it resembled his Rhynchonella scotica from Craighead, for the latter 

 is a Parastrophia with the characteristic generic features (see p. 929). C. Peachi. 

 is allied to the swollen transverse varieties of C. Thomsoni and to C. balclatchiensis, 

 as above described. It is thus also related to C. Volborthi, Billings, t from the 

 Black River Limestone, the genotype of Camarella. 



Horizon. — Stinchar Limestone Group. 



Locality. — Craighead. 



* Reed, Quart. Journ. Geol. Soc, vol. lxvi, 1910, p. 278. 



t Billings, Geol. Canada, 1863, p. 143, fig. 77 ; Hall and Clarke, op. cit., Bracli., ii, pi. Ixii, figs. 13-18. 





