290 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Mar. 25, 



2. Note on the Relative Position of the Strata, near Ludlow, 

 containing/ the Ichthyolites described by Sir P. Egerton*. By 

 Sir Roderick Murchison, V.P.G.S. 



The localities near Ludlow which afforded the fossil fishes described 

 by Sir P. Egerton were examined by me in July 1856, accompanied 

 by Mr. Lightbody, Professor Ramsay, Mr. Salter, and Mr. Aveline ; 

 and the relations of the strata were briefly explained in a notice 

 offered to the British Association at the Cheltenham Meeting. As 

 the abstract of that communication, published in the * Athenaeum,' 

 was somewhat inaccurate, and does not convey my matured opinion, 

 I here first place on record the statement which I intend to publish 

 in a second edition of my work * Siluria.' 



The section of the railway-cutting north of Ludlow exhibits an 

 upcast by which some of the highest beds of the Ludlow Rock are 

 brought up against Old Red Sandstone on the north-west. This 

 small insulated mass is manifestly distinct from, and younger than 

 the formerly described bone-bed of the Upper Ludlow Rockf. 

 That stratum, as described in my work, is overlaid by the Downton- 

 castle building-stone and other grey strata constituting the lower 

 portion of the * Tilestones,' whilst this band at the railway, in all 

 about 6 feet thick, is at once conformably surmounted on the south- 

 east by micaceous sandstone and red shale or marl. Though higher 

 in the series, this thin band still contains some characteristic fossils 

 of the lower course, such as the Plectrodus, sp., Onchus Murchisoni, 

 Ag., and the Lingula cornea. Sow. On the other hand, the following 

 species are unknown in any inferior stratum, viz. Cej^halaspis orna- 

 tus, Egerton |, Auchenaspis Salteri, Egerton §, Onchus or Byssacan- 

 thus, sp., together with Pteryyotus anglicus, Ag., and Eurypterus 

 pygmceus, Salter Ij. The two last-mentioned fossils, having been re- 

 cognized by Mr. Salter, are about to be described in full in the De- 

 cades of the Survey. 



The natural features on the right bank of the Teme, south of 

 Ludlow, i. e. between Ludford and the Paper-Mill, offer a more 

 satisfactory succession. They prove that the original bone-bed, 

 sloping down to the south-east at a very gentle angle, is covered by 

 strata representing the Downton-castle stone, the whole passing 

 under brownish, micaceous thin-bedded, sandstones, which, to the 

 east of the Corn-mill, are covered by red marl or shale, with minute 

 green concretions or cornstones. These strata are so much obscured 

 by drift and gravel, that the observer can detect the beds here and 

 there only, where the water is very low. It is therefore probable 

 that the thin fossiliferous band exposed at the railway, the inter- 

 mediate range of which is hidden by detritus, may still be discovered 

 on the banks or in the bed of the River Teme. However this may 

 be, another and still higher fossil band was discovered by Mr. Light- 

 body, and this is the "grit-bed," the fossil fishes of which are also 



* See above, p. 282. f Sil. Syst. pp. 197, &c., and Siluria, pp. 137, &c. 



X See above, p. 285. § See above, p. 286. 



II Quart. Journ. Geol. Soc. vol. xii. p. 99. 



