1855.] BANKS — TILESTONES OF KINGTON. 99 



about two or three inches in length. The surface appears to be 

 covered with shagreen, with an underlayer of minute closely-set 

 circular hollows, which traverse the surface with the greatest regu- 

 larity. 



A specimen of a Crustacean, probably a species of Eurypterus, 

 was found in the grey layer before noticed (see PI. II. fig. 4) ; it is 

 very imperfect ; the trace of the dermal covering is shght, and the 

 posterior segments, which would throw a greater light on its proper 

 position, are wanting. The posterior portion of the head, at the 

 junction with the thorax, is bounded by an almost straight line, 

 of an equal width with the bands, which are entire from side to 

 side and without any longitudinal depression. Mr. Salter proposes 

 to name it E. pygmcBus. One specimen which I lately found had 

 a distinct swimming-foot on the left side, resembling those figured 

 by various authors who have written on the genus. 



I have figured also some specimens of the Crustacean named Hi- 

 mantopterus Banksii by Mr. Salter*. The species is not uncommon 

 in the Kington beds, and is represented by detached heads (PL II. 

 figs. 5 0, 5 6, 5 c), body-rings (figs. 5 d, 5 e), and spines (fig. 6), 

 which are very possibly the caudal spines. 



It is very probable that traces of the same remains will be found 

 to exist wherever the Downton sandstone (or tilestones) occurs and 

 is regularly quarried, but the continued working of the Bradnor 

 Quarry has afforded unusual means of investigation. In a quarry 

 abandoned, or where the strata are merely exposed, there is neces- 

 sarily but little opportunity of learning the contents of the beds ; 

 for in many portions of the tilestone beds an occasional slight 

 marking is the only indication of the existence of these remains, 

 while in other portions they occur congregated together in great 

 abundance. 



Adopting the test made use of by M. Alcide d'Orbignyf in order 

 to ascertain whether these beds belong to the Old Red Sandstone, 

 as was originally considered by Sir R. Murchison, or to the Ludlow 

 Rocks, — the absence of the Mollusca of the Ludlow Rocks and the 

 presence of Fishes and Crustaceans, which have never been found 

 in the Ludlow Rock, and the greater development of Pterygotus, 

 which occurs in Scotland in the middle beds of the Old Red Sand- 

 stone I, lead to the conclusion that these Downton, or Tilestone beds, 

 should be considered as separate from the beds in which the Mol- 

 luscs of the Upper Ludlow rock occur, and be classed as the bottom 

 beds of the Old Red Sandstone. 



Doubtful as it is whether the buckler-Hke fossil remains above 

 referred to belonged to Fishes or to Crustaceans, it is certain that 



* Quart. Journ. Geol. Soc. No. 45. p. 32. 



t Cours elementaire de Paleontologie, vol. ii. pp» 245, 256. Caracteres strati- 

 graphiques negatifs, § 1598. Car. strat. positifs, § 1598. Des exceptions aux 

 limites desfaunes geologiques, §§ 1605 — 1609. 



X See MiUer's 'Old Red Sandstone,' 5th edit. p. 177-179. 



