664 



ME. J. E. MAKE AlfD DE. H. A. KTCHOLSON 



noticed before, and the Atrypa-flexuosa band, which is one foot thick, 

 contains a number of fossils, including : — 



Climacograptus normalis, Lapw. 

 Atrypa flexuosa, n. sp. 



Strophomena. 

 Homalonotus ? 



The breccia of the strike-fault is here seen immediately above the 

 limestone, nor do we meet with any exposure of the Dimorphograp- 

 tus-confertus Beds on the left bank of the stream above this point, 

 the strike-fault usually occurring in the bed of the stream and bring- 

 ing the Middle Skelgill Beds against the Atryim-fleocuosa Zone or 

 even the Ashgill Shales. 



At one point however, in the moorland portion of the stream, a 

 very good exposure of the DimorpTiograptus-confertus Beds occurs 

 on the right bank. This is about a hundred yards below the 

 Upper Bridge. Below the Upper Bridge the stream makes a bend, 

 leaving a promontory mainly composed of the Middle Skelgill Beds in 

 a greatly shattered condition, and at the south-west corner of the 

 promontory the Dimorpliograptus-confertus Beds are seen dipping so 

 as to pass beneath the Middle Skelgill Beds, though a short interval 

 occurs between them, certainly occupied b}' the usual strike-fault, the 

 breccia of which is seen in places. 



The Dimorphograptiis-beds consist of blue mudstones, here break- 

 ing into rectangular fragments, and resting on the Ashgill Beds, 

 against which they are crushed, as shown by the absence of the 

 Atrypa-Jlexuosa band, and the disturbed character of the Dimorpho- 

 grajjtus-heds, where brought against the Ashgill Shales. The fossils 

 here are somewhat different from those seen at the Lower Bridge. 

 "We have found : — 



Monograptus revolutus, Kurck. 



Sandersoni, Lapw. 



attenuatus, Hop/c. 



tenuis, Portl. 



Dimorphograptus confertus, Nick. 



Swanstoni, Lapw. 



Diplograptus vesiculosus, JSlch. 

 modestus, Lapw. ? 



Of these, Diplograptus vesiculosus, Mch., Dlmorpliograptus Swan- 

 stoni, Lapw., and Monograptus tenuis, Portl., are abundant, whilst 

 Bimorpliograptus confertus, Mch., is rarer. We consider that thess 

 beds are somewhat higher in the series than those occurring at the 

 Lower Bridge : — first, because the D. -confertus Beds at the Lower 

 Bridge immediately succeed the Atrypa-Jlexuosa Limestone; and 

 secondly, because Monograptus tenuis is comparatively abundant in 

 the shales immediately below the strike-fault in the cliff just below 

 the Lower Bridge, whilst it is much rarer lower down the cliff, 

 where Dimorphograptus confertus, Mch., becomes so abundant. 

 JSTevertheless we are not prepared to divide the DimorpTiograptus- 

 confertus Zone into a lower band characterized by the abundance oiD. 

 confertus, Mch., and an upper band characterized by the comparative 

 scarcity of D. confertus, Nich., and the abundance of D. Stva^istoni, 

 Lapw., and oi DipAograptus vesiculosus, Nich., and Monograptus tenuis, 

 Portl., though we think it is highly probable that this might be done. 



Before passing on to describe the Middle Skelgill Beds, we may 

 sum up the results we have arrived at : — 



