lxXXvi PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



band still contains some characteristic fossils of the lower course, such 

 as Plectrodus, Onclius Murchisoni, and Lingula cornea : it contains a 

 large majority unknown in any inferior stratum, viz. — Cephalaspis 

 omatus, Eg., a species of which Sir Philip expresses a belief that fu- 

 ture specimens may reveal further characters, and lead to its union 

 with C. Murchisoni ; Auchenaspis Salteri, Eg. ; Onclius or Byssacan- 

 thus; Pterygotus anglicus, Ag., and Eurypterus pygmceas, Salter; — 

 the last two fossils having been recognized by Mr. Salter, who will 

 describe them in the Survey Decades. Sir Roderick points out the 

 manner in which the strata are so obscured by drift, that they can only 

 be discovered here and there in the river-bank, where the water is very 

 low, and hence suggests that the Railway-band, though its interme- 

 diate range is concealed by detritus, may yet be discovered in the banks 

 or in the bed of the Teme. A fossil-band, called the Grit-bed, com- 

 posed of a whitish-grey micaceous sandstone, was discovered by Mr. 

 Lightbody higher in the series : it contains several of the fossils which 

 have been mentioned, together with fragments of Crustacea and copro- 

 lites ; and, as amongst its fossils some of those most characteristic 

 of the lowest of the bone-beds are found, it might at first be sup- 

 posed to exhibit, though associated with red and green marls, the 

 last remnant of Silurian life, were it not that other fossils show that 

 it marks a passage upwards into the Old Red or Devonian system, 

 and forms, in fact, the uppermost layer of the tilestones, whilst 

 the red marls, sandstones, and cornstones which follow, with the 

 Cephalaspis Lyellii, Pteraspis Lloydii, &c, form the great overlying 

 masses of Old Red Sandstone. The determination of the true ge- 

 neric position of fossils must always be an important element towards 

 the accurate identification of strata ; but with every aid there must 

 be many difficulties in settling the true age of strata which are con- 

 nected with a drift-period; and the observation, therefore, of Sir 

 Roderick in respect to the tilestones of Shropshire and Herefordshire, 

 M that they may be classed either with the Silurian or the Devonian, 

 according to the predominance of certain fossils," is both just and 

 philosophical. 



A conjoint paper by Sir Philip Egerton and the Rev. P. B. Brodie 

 contains an account of the discovery, by the latter geologist, of a new 

 species of Palceoniscus in the Upper Keuper Sandstone, at Rowington, 

 near Warwick, and a careful ichthyological description of it by Sir 

 Philip. In this he points out the difference, as regards the remote 

 position of the dorsal fin, which separates it from all the other known 

 species of the genus except the little P. catopterus of Roan Hill, 

 county of Tyrone, Ireland, formerly considered to belong to the New 

 Red Sandstone, but now transferred, as other supposed portions of 

 the same formation have been, to the Permian.; Though the speci- 

 men was not perfect, Sir Philip considered it sufficient to prove that 

 it was a true heterocercal fish, and not one exhibiting a transition 

 between the heterocercal character of Permian and other earlier 

 strata, and the homocercal character of the Liassic fish. The dorso- 

 ventral scales are arranged in gentle curves, which give an appear- 

 ance of much elegance to the species, which is named by Sir Philip 



