and Relations of the Frontier Chain of Scotland. 257 



old red sandstone, with a comparatively low angle of inclina- 

 tion, rests on the edges of the older rocks, and runs up the 

 deep bays and hollows of the frontier chain ; and (as shewn 

 by Mr Stevenson) in one or two instances, passes almost con- 

 tinuously through it. Similar phenomena are seen among 

 the mountains of the great Cumbrian group, which were pro- 

 bably elevated contemporaneously with the frontier chain of 

 Scotland. 



This chain does not appear to have undergone any great 

 elevation during the whole carboniferous epoch ; for the new 

 red sandstone, after this epoch, plays the same part that was 

 before played by the older red sandstone, viz., it rests uncon- 

 formably on the older rocks, and runs up their deep indenta- 

 tions and hollows, sometimes so as almost to traverse the whole 

 chain, a fact which has led to much misapprehension and many 

 false colours on the Scotch geological map, on which the old 

 and new red sandstone have often been confounded. 



List of Organic Remains. By Professor M^Coy, 

 First, or Moffat Group. 

 Graptolites Sagittarius, Lam. ; G. tenuis. Port. ; G. convo- 

 lutus. His. ; G. millipeda, M'Coy, n. s. ; G. lobiferus, M'Coy, 

 n. s., common ; G, Sedgrvickii, Port. ; Diplograpsus rectangu- 

 laris, M'Coy, n. s., common ; D. pristis, common ; D. folium, 

 His. ; Protovirgularia dichotoma^ M'Coy. Localities. — East 

 and west of the road from Lockerby to Moffat, Hart Fell, 

 Moffat Water Head, &c. 



Second Group. 



Mgrianites tenuis, M'Coy, common ; Graptolites tenuis, 

 Port. ; G. Sedgrvickii, Port. ; G. Ludensis, Murch. Locality. 

 — Grieston, on the Tweed. Crossopodia Scotica, M'Coy, very 

 common. Locality. — Thorneyley, on the Tweed. Diplo- 

 grapsus mucronatus, Hall (Diplograpsus is a new genus pro- 

 posed for the double-celled Graptolites ;) D. sextans, Hall, 

 very common (an Utica slate species) ; D. pristis. His. Lo- 

 cality. — Cairn Ryan. 



Third, or South Girvan Group. 



Orthis (large species allied to 0. flabelluin)^ very common ; 



