360 ME. E. S. COBBOLD ON THE [vol. lxxvi, 



Prof. Charles Lapworth was the first to point out that the 

 Olenellus and Paradoxides Zones were in contact in the Shrop- 

 shire area, and he has also shown very great interest in the 

 explorations conducted at Comley for the British Association. It 

 seems, therefore, appropriate to dedicate a genus that marks, at 

 least locally, the dividing-line between the Lower and Middle 

 Cambrian to his honour. 



Lapwoethella nigea, sp. nov. (PI. XXI V, figs. 1-6.) 



Salterella (perhaps 2 spp.), Cobbold, 1909, "Rep. Brit. Assoc. (Dublin, 1908) p. 235. 

 Salterella Cobbold, 1910, Q. J. G. S. vol. lxvi, p. 20. 



Type-specimens [270, 267] ; also [EE. 1221], Geological Survey 

 collection. 



Diagnosis. — Shell: a small, pyramidal or conical, curved tube, 

 divided into from twelve to twenty annulations ; rate of taper, 

 variable, from 1 in 1"4 to 1 in 4%3 (equivalent apical angles 41° to 

 13°) ; aperture transverse, varying from sub-circular to sub-rhom- 

 boidal ; apex sharp; shell-substance of two layers : (1) inner layer 

 moderately thick, calcareous and annulated on the exterior by 

 prominent ridges, which are at right angles to the curved axis of 

 the tube, pass all round it, and are set at nearly uniform distances 

 apart; (2) outer layer very thin, of black, chitinous (?) material, 

 which passes over the transverse ridges giving them a sharp edge ; 

 interior of shell smooth, or slightly marked by annular lines of 

 thickening corresponding to the transverse ridges. No septa or 

 operculum have been observed. 



Dimensions. — Lengths = 2 to 3 mm. ; diameter of aperture = 

 2 to 1*5 mm. 



The species is very variable : not only is there a considerable 

 range in the apical angle, but the sectional form is not constant. 

 Some specimens appear to be truly circular, others are more or less 

 semicircular, and others again are sub-trapezoidal. There is also 

 much variation in the spacing of the encircling ridges. 



Localities and horizon. — Comley and Neve's Castle; from 

 the LapioortheUa Limestone, horizon Ad. 



Saltebella Billings. 

 Saltebella (?) bella, sp. nov. (PI. XXIV, fig. 33.) 



Type-specimen [523]. 



Diagnosis. — Shell a small, tapering, curved tube with elliptical 

 aperture, axes in the proportion of 1 to *6, rate of taper 1 in l - 5 r 

 equivalent apical angle 40° ; shell-substance calcareous, thick, and 

 strong ; exterior marked with numerous, delicate, impressed stria? 

 of growth and from five to eight irregular constrictions ; no radial 

 striae ; apex not preserved. 



Dimensions. — PIeight=:l - 25 mm. ; longer diameter of aperture 

 = 1 mm. ; length = 1*5 mm. 



