1863'.] 



ROBERTS CRUSTACEAN TRACKS. 



233 



2. On some Crustacean Tracks from the Old Red Sandstone near 

 Ludlow. By George E. Roberts, Esq. 



[Communicated by the President.] 



I lately received some sandstone-slabs from the Lower Old Red 

 Cornstones, obtained by Mr. Alfred Marston, of Ludlow, which ex- 

 hibit more clearly than is usual tracks and trails of Crustacea. They 

 were obtained from a somewhat noted quarry at Bouldon, a village 

 seven miles north of Ludlow. Mr. Marston has furnished me with 

 the following details of the Bouldon section : — 



Eig. 1. — Vertical Section of the Beds exposed at Bouldon Quarry, 



near Ludlow. 





ft. in. 



a. Rough coarse conglomerate ; a few Fish-remains 



(Pteraspis, Cephalaspis) 5 



b. Fine-grained sandstone with Pteraspides .... 1 3 



c. Fvubbly beds 6 



d. Fine-grained sandstones with Pteraspides ... 1 6 



e. Micaceous sandstones 10 



f. Thin-bedded fine sandstone with tracks of Crus- 



taceans 4 



g. Fine-grained shales 8 



h. Lowest Cornstone ; remains of Fish and Crus- 

 taceans ; Pteraspis and Cephalaspis abundant, 

 Pterygotus scarce. 



A zone of fine-grained and thin-bedded deposits, indicating qui- 

 escent conditions and shallow water, is thus seen dividing two con- 

 glomeratic beds, the lower of which I am inclined to regard as the 

 rock wanting above the plant-bearing bed at Linley, but which is 

 seen to accompany that deposit at Trimpley, in Worcestershire, and 

 elsewhere. 



The Crustacean tracks occur as casts abundantly upon the under 

 surface of the thin sandstone-layer, /, of the above section. 



Of the three or more varieties, the most important in size and 

 distinctness (fig. 2) is a slightly curved trail about \\ inch in width, 

 formed by two series of oval or, rather, flask-shaped prints, \ of an 

 inch long, each bearing a number of transverse wrinkles parallel 

 to the direction of the trail. The prints taper inwardly, and have 

 a slight upward curve at the same end. Their distance from each 

 other varies, as also does the height of the cast, but these inequali- 

 ties may be regarded as results of peculiarities of the condition of 

 the surface which received them. 



The indentations made by another Crustacean (?) upon the slabs 

 (see fig. 3) are longer and more sharply ended, and show a nearer 



