On the Geology of Moffat, Dumfriesshire. 383 



are most hooked towards the ends of the rays. There is 

 however, a peculiar feature to be noticed in this species : 

 although it has not the jaw-like spine, it is furnished with 

 " two little obsolete or undeveloped spines/' Ophiocoma 

 rosula and Ophiocoma bellis have one only of these " obsolete 

 spines" — valves I would rather call them — for an opening 

 may be seen when these are raised, out of which the pin- 

 nated cirrhi are protruded. I regret exceedingly that I can- 

 not find the drawings of Ophiocoma rosula where these cirrhi 

 are shown, and which I sketched from a living specimen. 

 I find in a specimen of Ophiocoma Ballii that the lowest 

 spines on the under side of the rays are crowned with small 

 hooks ; and I have every reason to believe that most of the 

 Ophiocoma are more or less provided with hooks, either on 

 straight or jaw-like spines. 



Description of Plate XX. 



Fig. 1. — Part of a ray of Ophiocoma bellis, showing spines, valves, &c. 

 Figs. 2, 3, 4, 5, 6, 7, 8.— Spines from various parts of the ray. 

 Fig. 9. — Part of a ray of Ophiocoma granulata, showing spines, &c. 

 Fig. 10. — One of the uppermost spines. 



Fig. 11. — Hooked spine from the under side of the tip of a ray. 



VII. The Geology of Moffat, Dumfriesshire. By William 

 Carruthers, Esq., F.L.S. 



Lithology. 



I purpose in this paper describing the geological features of 

 the district around Moffat, taking the village as my centre, 

 and including all that lies within a radius of four or five miles. 

 The district is situated in the centre of" the immense Silurian 

 tract of the south of Scotland ; its predominant rocks conse- 

 quently belong to the Silurian period. A red sandstone lying 

 unconformable to them is the only other stratified rock. The 

 superficial deposits are not numerous ; they consist of boulder 

 clay, gravel and sand, peat and shingle. A trap-dyke, which 

 runs through the district a mile below Moffat in a south-east 

 direction, is the only igneous rock with which I am ac- 

 quainted. 



VOL. II. 3 D 



