0. LAPW0RTH ON THE MOFFAT SERIES. 267 



group of black, grey, and purple beds, faulted against the grey wackes 

 of the country to the south. These faulted beds yield Monograptus 

 spinigerus (Nich.) and M, Hisingeri (Carr.), and are clearly a 

 portion of the Upper Birkhill group. 



Bisldnhope Burnfoot. — Following the general direction of the 

 band along its line of strike to the south-west, it is seen to cross the 

 mound-like ridge of Peat Hill at a very oblique angle, and its strata 

 are again visible near the mouth of Eiskinhope Burn. Here the 

 shales are too contorted and broken to enable us to make out the 

 sequence ; but the mineralogical characters and fossils of the central 

 and more convoluted beds are recognizable as those of a portion of 

 the Lower Birkhill group. The terminal strata are less shattered. 

 They yield a few exquisitely preserved Upper Birkhill forms, and 

 pass distinctly below the greywackes to the north at a high angle. 



For the succeeding mile and a half, the position of the band is 

 indicated by a peculiar road-like indentation in the smooth grass- 

 grown flank of Muckra Hill. It arrests the drainage of the hill- 

 slope and gives rise to a row of perennial springs. 



Fig. 6. — Section in Muckra Burn, 



ISTE. 



a,*. -~ • C*3. 



D. Flagstones and greywackes of the Gala group. Cb. Contorted grey shales. 

 Cb 3 . Grey shales with black and white seams, containing Rastrites maximus, 



Monograptus Halli, &c. 

 Cb' 1 . Grey shales with black bands and seams of white clay, with Monograptus 

 spinigerus, M. Clingani, M. Hisingeri, trails of Annelids, nodular con- 

 cretions, &c. 

 2. Horizon of Monograptus spinigerus. 3. Horizon of Rastrites maximus* 

 Ca. Black flagstones and shales, greatly shattered, non-fossiliferoua. 

 Bb. Pale flaggy mudstones and shales. 

 /. Fault, 



Muckra Burn (fig. 6). — The second important exposure of the rocks 

 of this band is met with in the Muckra Burn, which is crossed ob- 

 liquely by the dark shales at a point about midway along its length. 

 As in the former instances the beds in the southern (or inverted) 

 portion of the exposure are so shattered and altered that their 

 detailed identification is well-nigh impossible. There ia, however, 

 enough visible to enable us to assure ourselves of the fact that 

 they are actually arranged in an anticlinal form. The central beds 

 resemble the " Barren Mudstones " of the Hartfell Shales. They are 

 followed on both sides by black beds which come into the place of 

 the Lower Birkhill Shales. These are succeeded, in their turn, by 

 the grey and blaek beds of the Upper Birkhill, which to the south 

 are visibly in conformable contact with the greywackes. 



The structure of the northern half of the exposure, however, is 

 perfectly dear. Its beds are those of the grey division of the Birk- 

 hill Shales, much convoluted and fractured, but very slightly altered. 



t2 



