part 4] CAMBRIAN HORIZONS OF COMLEY. 363 



Locality and horizon. — Comley (Shropshire), Lower Cam- 

 brian. 



These tubes agree with Holm's genus ToreleUa in their elliptical 

 section and sub-parallel margins; but there is no trace of the phos- 

 phatic shell of that genus, and the wall of the tube is very different. 



The external aspect recalls that of Salterella, but the elongate 

 form of the tubes and the absence of any sign of the cone-within- 

 cone structure of the shell preclude any reference to that genus. 



Salopiella obliqua, sp. nov. (PI. XXIV, figs. LS^-lSc.) 



Type-specimen [242] . 



Diagnosis. — Shell tubular, thin, slightly curved, and having a 

 very slight taper ; section elliptical, ratio of diameters 1 to *55. 

 Shell-substance calcareous (P) ; shell-structure consisting of a 

 number of angular step-like corrugations which are spaced about 

 12 to the millimetre, pass obliquely round the tube, and are 

 reproduced on the interior. One slope of these corrugations is 

 nearly parallel to the axis of the tube, the other is very steeply 

 inclined to it. 



Dimension s. — Larger diameter = about "6 mm. ; greatest length 

 seen = 3 '5 mm. 



Observations. — The type-material consists of an internal cast 

 in calcite [212] and a partly internal, partly external cast in sandy 

 limestone [231]. The shell appears to have been calcareous, for in 

 the second specimen it has entirely disappeared, with no trace 

 of any phosphatic material. 



Locality and horizon. — Comley, Lower Cambrian; from the 

 StrenueUa Limestone, horizon Ac 4 . 



Helen [A Walcott, 1S90. 

 Helenia cancellata, sp. nov. (PI. XXIV, figs. 7^-10.) 



Helenia Cobbold, 1911, Q.J.G.S. vol. lxvii, p. 297. 



Type-specimens [245, 246]. 



Diagnosis. — Shell: a flattened curved tube, tapering very 

 gradually to a blunt, closed end ; section, a narrow oval ; shell- 

 substance thin, phosphatic ; exterior beautifully sculptured by two 

 sets of impressed lines running obliquely across the shell and 

 leaving minute, diamond-shaped projections between them. 



Dimensions. — Diameter = about - 5 mm.; greatest length seen 

 = 6 mm. 



Observations. — Usually there is a longitudinal depression 

 close to the concave margin — it does not reach the closed end, is not 

 seen at all in one specimen, and is probably due to the collapse 

 of the tube. 



The type-species of the genus, H. bella "Walcott, 1 is described as 

 • probably open at both ends ' ; it has but one set of diagonal lines. 



II. granulata Matthew 3 is described as having a minutely 



1 1889, p. 39 ; and 1890, p. 610 & pi. lxxviii, figs. 4, 4 a-4 b. 



2 1899 a, p. 192 ; 1899 b, p. 107 & pi. vi, figs. 7 a-7 e. 



