W. D. Varney — " Coal-balls," Aonbergate, Derbyshire. 471 



of the stout tail-spine, which is 1 ram. in breadth, but is only 

 imperfectly preserved (length unknown). 



There seems to be good evidence that the division (A) of Palaeozoic 

 "king-crabs" represented in the Coal-measures by the genus 

 Bellimirus contains the oldest form of the Xiphosura, which take 

 precedence, in time, over those with anchylosed segments referred to 

 tlie division (B) represented by the genera Predwichianella and 

 Euproops, as evidenced by their precursor, Neolimulus falcatus, 

 H Woodward,! 1868. 



This earliest known form from the Upper Silurian appears to liave 

 had all its segments free and unanchylosed, and the later form 

 Bellinurus kiltorhnsis, Builj, from the Old Eed Sandstone, probably 

 represents the same genus as is met with in the Coal-measures with 

 free thoracic, and most of them had anchylosed post-thoracic somites. 





Fig. 5. — Bellinurus Trechmanni, H. Woodw., sp. nov. x 4. Upper Coal- 

 measures : Claxheugh on the Wear, Sunderland. 



The entire series of species of Bellinurus Yarj \itt\e in their general 

 characters. They are all of small size and possessed a long caudal 

 spine and rather marked triangular thoracetron. 



The specific characters of the Durham specimen are the obviously 

 shorter and outwardly directed cheek-spines, and the broader and 

 more parallel-sided axis of the thoracetron, which is proportionately 

 larger than in the other species of this genus. 



I dedicate this species, which is the first that has been discovered 

 in this great coal-field, to Mr. C. T. Trechmann, whose admirable 

 contributions to the palaeontology of New Zealand have already 

 appeared in the pages of the Geological Magazine and elsewhere. 



IV. — On the Occuerence of "Coal-balls" neak Ambergate, 



Derbyshire. 

 By W. D. Varney, B.Sc, University College, Nottingham. 



IN the brick-pit cut into the Lower Coal-measures at BuUbridge, 

 near Ambergate, the Alton Coal is exposed, immediately over- 

 lain by a marine shale roof, containing large nodules (bullions) and 

 marine fossils. 



! See Geol. Mag., PL I, Fig. 1, and Men. Pal. Soc, 1878, pt. v, Xiphosura, 

 pp. 233-5, vroodcut, and pi. xxxi, fig. 8. 



