310 C. LAPWOttTH ON THE MOFFAT SERIES. 



and of an intense black. These, again, support two feet of some- 

 what similar beds, distinguished, however, by the presence of nume- 

 rous thin ribs of hard grey rock. Above follows the thick mass of 

 black flags forming the base of the D.-Clingani zone. 



The whole of the C.-Wilsoni beds are totally barren of fossils, 

 except in a few thin seams, where the laminae are of a coarser or 

 more open texture than usual. These swarm with Graptolites in 

 admirable preservation. The forms collected from this zone at 

 Hartfell Spa are given in the following list : — 



Leptograptus flaccidus (Hall). 

 Dicranograptus Nicholsoni (HopJc.). 



ramosus (Hall), 



Climacograptus Wilsoni (Lapw.). 



bicornis (Hall). 



, var. tridentatus (Lapw.). 



Scharenbergi (Lapw.). 



Diplograptus foliaceus (Murch.). 



tricornis (Carr.). 



truncatus (Lapw.). 



Glossograptus Hinoksi (Hop/c). 

 Lasiograptus Harknessi (Nick.). 

 Corynoides calycularis (Nick.). 

 Discina, sp, 



At Dobb's Linn the band of flinty shale at the base of the zone 

 agrees precisely in thickness and in mineralogical character with 

 that of Hartfell Spa. It is immediately succeeded by the 2| feet of 

 platy shales. Here, however, the intercalated coarser seams have' 

 no longer the spotted appearance of those of Hartfell, but are softer 

 and more finely laminated, and make up a much larger proportion 

 of the beds. The remainder of the zone is formed by the deep 

 black shales, here almost destitute of the thin ribs of harder rock, 

 but containing more of the soft grey or cream-coloured bands 

 (fig. 27). 



The fossils are restricted as before to a few of the softer and 

 coarser laminae. In these they are found in a state of high relief, 

 far exceeding in beauty of preservation those collected from any 

 of the succeeding zones. Even the grey beds yield occasionally 

 traces of the life of the period in the shape of burrows of Annelides, 

 skeletons and spicula of sponges, small Orbiculce, and the like. 



These beds have been studied more particularly than those of 

 Hartfell ; but no forms have been detected in addition to those given 

 in the foregoing list, all of which, are present in abundance. 



The C.-Wilsoni zone forms the inferior portion of the partially 

 inverted synclinal of Hartfell Shale visible in the Black Linn of 

 Glenkiln Burn (fig. 19, p. 286). It is beautifully shown on the north 

 side of the trough. It has here a thickness of about 8 feet. The 

 dark flaky shales, though present, appear to be far less abundant 

 than in the two former localities, and there is a simultaneous 

 increase in the amount of grey shale and flagstones. The hard 

 grey ribs seen at Hartfell Spa, but almost absent from the sec- 

 tion in Dobb's Linn, are here very numerous, and give to the 

 section generally a marked similarity to those in exposures of the 

 Glenkiln division. The intractable bed at the base of the zone is 

 slightly thicker than usual, and does not exhibit such clear traces of 

 stratification. 



Fossils are rare. As usual, they are in a state of half-relief. 



