On some Crustacean Tracks from the Old Red Sandstone near Ludlow

Abstract

I lately received some sandstone-slabs from the Lower Old Red Cornstones, obtained by Mr. Alfred Marston, of Ludlow, which exhibit 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:— A zone of fine-grained and thin-bedded deposits, indicating quiescent conditions and shallow water, is thus seen dividing two conglomeratic 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, f , 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 one and one-half inch in width, formed by two series of oval or, rather, flask-shaped prints, one-quarter 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 inequalities 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