88 



Description of Entomostraca, &c. 



Fig. 3. 

 Beyrichia Tatei, Jones. 



Trom the Carboniferous 

 shales of Brunton near 

 ChoUerford. 



" Carapace-valves somewhat Leperditia-shaped, about 

 l-20tli of an inch long, nearly oblong, boldly rounded be- 

 hind, less so in front; ventral margin flatly convex ; hinge- 

 line straight ; postero-dorsal angle more distinct than 

 the anterior angle. Valves smooth, 

 moderately convex, depressed towards 

 the margin ; impressed with a very shal- 

 low transverse sulcus, reaching from the 

 middle of the back to the centre of the 

 valve. In one specimen the pyritous 

 cast seems to show that radiating, sinous, 

 A tapering furrows existed on the inside of 

 the shell, as in Leperditia. 



" This Beyrichia reminds us of the 

 little Silurian Beyricliice of Canada, 

 figured and described in the Annals of 

 Nat. Hist., ord Ser. vol. i. pi. 9., in 

 ^ which a simple furrow and a tendency to 

 a Leperditia-like form are characteristic. 

 This Betjrichia is about the size of some 

 of some of the smaller of the Canadian 

 specimens referred to, but has its own 

 style of outline, profile, and sulcus. By 

 the name now given to it, this species will be associated with 

 the enthusiastic and pains-taking geologist, Mr G. Tate, 

 F.G.S., of Alnwick, who has so well and so long worked out 

 the history of the Carboniferous rocks of the Border Coun- 

 ties." [T. Rupert Jones, 1863.] 



This Beyrichia is from a black 'shale, which is below the 

 " big limestone " at Brunton, near ChoUerford, on the North 

 Tyne, and about the middle of the Mountain-limestone series 

 of Northumberland. Containing both carbon and iron it is 

 similar to the black ironstone band of the Glasgow district, 

 which is valuable not only for the excellence of the iron it 

 produces, but also because of the carbon in the band helping 

 to smelt the ore. The shale at Brunton is peculiar from the 

 assemblage of the fossil organisms it contains, resembling in 

 this respect the Lammerton bed. Besides crowds of Ento- 

 mostraca, there are great numbers of detached scales and 

 other reliquiae of Ganoid fish, such being indeed the usual 

 state in which fish-remains are found where Entomostraca 

 are abundant ; for these little creatures seem to have at- 

 tacked the fish as soon as they died, and, devouring the flesh 



(a) Left valve, -with the 

 dorsal edge upwards. 



(b) Profile of the valves 

 united, back view. 



(Magnified 20 diameters.) 



