SALTER! A PRIM^VA. 43 



and overhanging sides of posterior half as small lobes strongly marked off behind 

 by deep short oblique furrows; apex of anterior half (frontal lobe) slightly pointed 

 in front. Furrow marking off frontal lobe from cheeks narrow, weak. Occipital 

 furrow strong, straight, marking off rather broad occipital ring with median tubercle. 

 Cheeks convex, with neck segment marked off by strong neck furrow. 



Remarks. — The genus Shumardia (= Conophrys, Callaway) lias only been pre- 

 viously recorded from beds of Tremadoc age, including the Shineton Shales of 

 Shropshire, the DictyonemaShales of Malvern, and the Tremadoc of Penmorfa, 

 North Wales, in the British Isles. Abroad it has been found in Scandinavia (Cera- 

 topy ge-liimestone) ; the Tremadoc of La Montaigne Noire, S. France ; and the 

 Quebec Croup of Canada. There are two head-shields of S. scotica, the largest 

 2 mm. long, in Mrs. Gray's collection from Whitehouse Bay, and these supply 

 the materials for the above description. 



Affinities. — This species differs from S. salopiensis, Callaway (' Quart. Journ. 

 Geol. Soc.,' vol. xxxiii, 1877, p. 007, pi. xxiv, fig. 7) by the slightly pointed form 

 of the glabella, in which feature it agrees with 8. miqueli, Pompecki (' Neues 

 Jahrb. f. Miner., etc.,' 1902, vol. i, p. 5, figs. 2 a, b) ; but in other respects it seems 

 closely allied to the Shineton form. 



Collection, — Mrs. Gray. 



Horizon and Locality. — Whitehouse Group (M. Bala) : Whitehouse Bay. 



Genus SALTERIA, Wyville Thomson. 

 1. Salteria primaeva, Wyville Thomson, 1864. Plate IV, figs. 13, 14. 



1864. Salteria primseva, Wyville Thomson, Mem. Geol. Surv., dec xi, pi. vi, p. 1. 

 1876. Salteria primseva, Armstrong and Young, Cat. West. Scot. Foss., p. 16. 



1878. Salteria primseva, Etheridge, jun., Proc. Eoy. Phys. Soc. Edinburgh, vol. iv, p. 170. 



1879. Salteria primoeva, Nicholson and Etheridge, Mon. Silur. Poss. Girvan., fasc. ii, p. 199, pi. xiv, 

 fig. 5. 



1899. Salteria primoeva, Mem. Geol. Surv., Silur. Kocks Brit,, vol. i, Scotland, pp. 509, 674. 



Specific Characters. — The diagnosis of this species given by Wyville Thomson is 

 as follows : — " S. fere uncialis, lata, ovata. Caput semilunare, limbo angusto, brevi, 

 convexo, marginato ; glabella ovata, pyriformi, depress;!, genis tnulto majori, 

 utrinque puteis tribus brevibus notata; sutura facialis sub fronte ambit ui parallels,, 

 dein per quartam partem externam limbi conspicua subverticalis. Thorax articulis 

 truncatis. Cauda triangularis multisegmentata." 

 Dimensions. — 



Length of head-shield . . . 8'5 mm. 



Width of middle-shield . . . L6'0 „ 



