On some small Fossil Vertebræ from near Frome, Somersetshire

Abstract

I was favoured a short time since by receiving from Mr. Charles Moore, F.G.S., the discoverer of teeth like those of Microlestes in a probably Triassic deposit near Frome, an additional series of specimens, including, together with teeth unequivocally mammalian and having the characters of those of Microlestes , some vertebræ, more or less mutilated, of corresponding size, and similar mineral condition. These were discovered in a fissure containing derivations from the “Bone-bed” and from earlier (Mountain-limestone) and later (Oolitic) deposits. A small glass tube, numbered “5,” was stated in Mr. Moore’s list to contain “two little vertebræ.” These I first examined. One (and the most perfect specimen, figs. 1–5) is a dorsal, the other a caudal vertebra; both are biconcave ( i. e. the articular ends of the centrum are cupped); and in both the neural arch is confluent with the centrum. The body of the dorsal vertebra is laterally concave both vertically and lengthwise (fig. 3, c), the lower surface (fig. 5) being narrow, prominent, like a smooth obtuse ridge, slightly concave lengthwise, expanding somewhat, like the rest of the centrum, at the articular extremities, c : these are deeply cupped, of a circular figure, with a smooth, almost polished surface. A narrow parapophysis begins very near the fore part of the side of the centrum, and is continued upward and a little backward, contracted and ridge-like, to the di-apophysis on the side of the neural arch, figs. 1, 2, 4, d ; or, the parand di-apophyses are connected by an intervening