Peltura 

 scarabeoides. 



230 



the full grown examples agree with Salter's indication of the size, but 

 occasional larger head shields are found, that do not appear to differ essen- 

 tially from the type ; these have a middle piece to the head shield that 

 is 3 x 6 mm. measured at the axial line, but 3x7 mm. at the longest part 

 of the fixed cheek. * 



All the pygidia seem to have been broken up, and, are rare compared 

 with the head shields ; three or four examples of the comb-like rachial 

 part of the tail shield were seen. 



The young (or a small variety) differ considerably from the larger ones 

 in the form of the glabella ; this part is proportionately shorter (which 

 for a larval condition is unusual) and the front lobe is rounder and more 

 prominent. 



Horizon and locality. The limestone layers in the bottom of Band 

 C. 36. at Escasonie shore, East bay N.S. 



PELTURA SCAEABEOIDES, Wahlenb. 



1821 Entomostracites scarabeoides, Wahlenb. Petrif. Tell. Suec. p. 41 



t. i fig. 4. 



1822 Paradoxides scarabeoides, Brongn. Hist. nat. des crust, foss. p. 34 



t. iii fig. 5. 



1827 Olenus scarabeoides, Dalm. K. Vet. Akad. Handl 1826, p. 72. 

 1840 Peltoura scarabeoides, Milne-Edw. Hist. nat. des crust, torn, iii, p. 



344. 

 1847 Petura scarabeoides, Corda, Monog. der Bohmisch. Trilobit. p. 127, 



t. vi, fig. 68. 

 1866 Olenus scarabeoides, Salt. Mem. Geol. Surv. G. Brit. vol. iii, p. 301, 



t. 15, figs. 2-5. 

 1886 Peltura scarabeoides, Wahl., Trans. Roy. Soc. Can., vol. iv, p. 147 ; 



vol. viii, p. 126 ; vol. ix, p. 53. 



This characteristic species is that by which the presence of Cambrian 

 rocks was first recognized in Cape Breton. It occurs at McNeill brook, 

 east of Mira river and also at the Escasonie shore, in both cases marking 

 the presence of the Assise C. 3 b. of the St. John terrane. 



TRIARTHRUS BELLI, PL xvm, fig. 8. 



Bull. Nat. Hist. Soc. of New Brunswick, vol. iv, p. 412, pi. xvm, fig. 8. 



Triarthrus Only the middle piece of the head-shield is known ; this is sub-quad- 



Belli. rate, with narrow cheeks and anterior margin. 



