87G 11. ETHER1DGE, JUN., ON THE OCCURRENCE OF A 



is provided -with a strong central ridge, separated into two parts by 

 the cervical groove, and projecting anteriorly in the form of a strong 

 spine. The abdomen consists of six somites with pointed pleurae, 

 exclusive of the telson, which has double broad caudal appendages. 

 All these characters, or at all events traces of them, are discernible 

 in our fossil. On the other hand, one which was assigned by Mr. 

 Salter to his genus as particularly distinctive, viz. the serrated front 

 margins of the carapace, is not present here. Taking all things 

 into consideration, I think no better reference can be made than to 

 Anthrapalcemon. 



Mr. Woodward has shown that no generic difference exists be- 

 tween Anthrapalcemon Grossarti and A. {Palceocaraims) dubius, as 

 surmised by Mr. Salter. In the former of these species there is a 

 central ridge on the carapace (irrespective of other characters) 

 which does not reach the posterior margin, and no lateral ridges. 

 On the other hand the central ridge in A. dubius does so, and on 

 each side of it there is a lateral furrow, between it and the mar- 

 gins of the carapace. I have shown that on the carapace of the 

 present fossil there is a central ridge extending from the cervical 

 groove backwards to the posterior margin, flanked on each side by 

 two parallel lines, which may represent either two ridges or two 

 grooves. Whichever they may be, they are sufficient to show, 

 I think, a closer affinity with A. dubius than with A. Grossarti. 



I propose to associate with this interesting fossil the name of my 

 friend Mr. H. Woodward, P.B.S. (Anthrapalcemon? Wood wardi), to 

 whom I am indebted for much kind assistance and advice in palae- 

 ontological questions. 



5. Geological Position and Locality. 



The Calciferous Sandstone, or Lower Carboniferous series, is divi- 

 sible into two groups, as now adopted by the Geological Survey — an 

 Upper or Cement-stone group, and a Lower or Bed-Sandstone group 

 resting on the Old Red Sandstone. At Belhaven Bay, near Dunbar, 

 whence AP. Woochvardi was derived, the lower group consists of red 

 and white sandstones and marls, "probably not far from the top of 

 the Old Bed Sandstone"*, and immediately under " great masses of 

 igneous rock, in the form both of ash and f elspathic trap .... 

 These piles of volcanic material lie about the middle of the Calci- 

 ferous Sandstone series "f. 



A. ? Woodward! is preserved in an impure ironstone nodule from a 

 bed of red and mottled shale, according to Mr. Bennie, about 15 ft. 

 thick. The associated nodules contain a Modioliform bivalve in 

 abundance; and the enclosing shale a similar mollusk, with the 

 remains of Stigma/rice, Lepidodendra, some curious Ferns, and an 

 Esther ia in great abundance, which Prof. Rupert Jones, F.B.S., 

 cannot distinguish from E. Dawsoni, Jones $, of the Lower Carboni- 

 ferous of Horton Bluff, Nova Scotia. The same bed, in its lower 



* A. Geikie, Mem. Geol. Survey, No. 33, Scotland, 1866, p. 30. t Ibid. 



X Etheridge, Geol. Mag. Dec. 2, 1876, vol. iii. p. oTO. 



