284 C. LAPWORTH ON THE MOFFAT SERIES. 



Oraigmichan Scaurs, but no intelligible transverse sections are visible 

 till we reach the lower portion of BelcraigBurn, a small stream fall- 

 ing into the Annan about 4 miles from the town of Moffat (fig. 18). 



Kg. 18. — General Section, Belcraig Burn. 



D. Flaggy greywackes with shaly partings. 



Cb. Grey flaggy shales with lines of white clay and seams of black fossiliferous 

 shale. 

 3. Zone of Bastrites maximus. 2. Zone of Motiograptus spinigerus. 



Ca. Black flaggy shales with seams of coloured mudstone. Diplograptus vesi- 

 cidosus &c. 



Bb. Mass of flaggy muclstones pale, non-fossiliferous. 



Ba. Shattered slaty shales, with Leptograptus flaccidus, &c. 



Ab. Pale shales and flaggy beds, with band of thin black pyritous shales yield- 

 ing Coenograptus gracilis, Dicellograptus sextans, &c. ///. Faults. 



Here the black and grey shales and mudstones of the Moffat 

 Series are seen partly in the main stream, partly in the course of a 

 small tributary which enters from the south. The chief axis of the 

 master anticlinal into which the strata of the band are thrown is, as 

 usual, greatly inverted, all the beds without exception dipping at a 

 steep angle to the west- north-west. 



The south-eastern side of the arch shows an ascending succession 

 through the Birkhill Shales into the overlying greywackes : on the 

 opposite side the latter are buried beneath the coarse conglomerate 

 which here forms the basal bed of the Permians of Dumfries. 



The Glenkiln Shales occupy the centre of the anticlinal. In the 

 main stream they form a rude arch, and the only beds exposed are 

 the black flaggy highly siliceous shales seen at Dobb's Linn. They 

 afford Didymograptus super stes (Lapw.), Dicellograptus sextans, and 

 a few other forms. In the side stream, the group is represented by 

 the soft white and yellow beds of Craigmichan — barren, concre- 

 tionary, or with cuboidal fracture — together with two soft black 

 beds, much crushed, but affording numerous examples of such 

 characteristic forms as Didymograptus superstes (Lapw.), Coeno- 

 graptus gracilis (Hall), Dicellograptus sextans, &c. &c. 



To the north-west these Glenkiln beds are faulted against a mass 

 of the " Barren mudstone " of Upper Hartf ell age, which is admirably 

 exposed in both streams. As no convolutions are visible, its thick- 

 ness is apparently greatly in excess of that of the same zone in any 

 other known locality. At the junction of the streams, the mudstone 

 is underlain by a fragment of the Pleurograptus zone of the Lower 

 Hartfell, with Pleurograptus linearis (Carr.), Leptograptus flaccidus 

 (Hall), &c. The same zone recurs on the opposite side of the 

 Glenkiln Shales, and affords similar fossils. 



The Hartfell beds are faulted in their turn against the Birkhill 



