198 



FISH-BED OF THE UPPER LUDLOW ROCK* 



Ft. In. 



a. Red and yellowish Sandstone, covered and underlaid by red shale 5 0 



b. Yellowish Sandstone, somewhat micaceous (a good freestone) . 3 0 



c. Ditto ditto more highly micaceous 2 0 



d. Ditto ditto 4 0 



e. Thin yellow flag or tilestones, with much carbonaceous matter and ripple-marks on sur- 



face. In the lower part they have little mica, become blue-hearted, and pass downwards 

 into the greenish grey Downton- castle stone. 



The manner in which these beds overlie and graduate into the true upper Ludlow 

 rock is well seen in the cliffs between the old and new bridges. Proceeding from east 

 to west, the following strata are met with in descending order. ^ ^ 



Yellowish and brown, flag-like, micaceous sandstone, with small Lingulai, &c, as before 

 described. (Ludford House is built upon them ; they are the bottom beds of the quarry 

 ^ at Richard's Castle, or beds of passage into the Old Red Sandstone.) 10 to 12 0 



1. Downton-castle building sione ; greenish grey, slightly micaceous Sandstone, in beds from 



2 to 4 inches thick, containing a few organic remains, such as Leptatna lata 12 to 14 0 



2. Fish-bed. The upper and lower parts consist of very finely laminated, argillaceous, greenish 



grey sandstone, containing here and there a few fish scales, with abundance of other or- i 

 ganic remains, peculiar to the upper Ludlow rock, such as the characteristic shells repre- 

 sented in PI. 5., viz. Leptcena lata, fig. 13. ; Orbicula rugata, fig. 11 ; Cypricardia amy- 

 gdalina, fig. 2. ; Trochus helicites, fig. 5. ; Avieula lineata, fig. 10. ; Bellerophon globatus, 



PI. 3. fig. 15, with zoophytic remains 1 8 to 10 0 



The beds 1. and 2. are best seen in a low cliff on the west side of Ludford turnpike gate. 



The central part of this stratum, which seldom exceeds two or three inches in thick- 

 ness, and occasionally dwindles to a quarter of an inch, running out into thin em- 

 branchments, is a matted mass of scales, ichthyodorulites, jaws, teeth, and coprolites 

 of fishes. These, together with a few small testacea, are united by a gingerbread- 

 coloured cement, in which varying proportions of carbonate of lime, iron, phosphate of 

 lime, and bitumen, are disseminated. Many of the imbedded fragments are of a jet black 

 colour and high polish ; others of a deep mahogany hue. So brilliantly black are 

 many of the organic fragments, that when discovered, this bed conveyed the impression, 

 that it inclosed a triturated heap of black beetles cemented in a rusty ferruginous paste. 

 This bed was first made known by laying open the rock for the foundation of a house 

 at Ludford, and might have escaped notice without the vigilant attention of my friends 

 Dr. Lloyd and the Rev. T. T. Lewis. I have since traced it in other contiguous spots 

 in the cliffs opposite Ludlow, and Mr. R. W. Evans of Kingsland has worked out its 

 contents with great zeal, and has discovered other remains of fishes in the overlying 

 and underlying strata, to which I shall allude in the sequel. This bone bed is not 

 merely local, since fragments having the same structure, but of greater thickness than 



i All the organic remains of the Silurian System will be described in a subsequent chapter, following the de- 

 scription of the fossils of the Old Red System. This arrangement, which will have the advantage of easy 

 comparison and reference, has indeed been rendered imperative, from the delays attending the completion of 

 the plates. The organic remains mentioned in the text, are a few only of the most common species. 



