C. LAPWORTH ON THE MOFFAT SERIES. 



295 



Hartfell Shales. 



Nowhere throughout the whole of the Moffat district or, indeed, 

 in any single locality in the south of Scotland, is there to be seen so 

 magnificent an exposure of the black flaggy beds of the middle divi- 

 sion of the Moffat Series as is exhibited in the northern cliffs in the 

 score at Hartfell Spa (fig. 23). It is for this reason that I have 

 grouped the whole of the beds of this division under the general 

 title of the Hartfell Shale, though the higher or Barren-Mudstone 

 subdivision is far less conspicuous than in the sections to the south 

 of the Moffat valley, and the terminal or D.-anceps band can no- 

 where be recognized. 



Fig. 23. — Section through the upper end of Hartfell Score. 



S.E. 



N.W. 



B. Grits and flagstones. Cb. Grey shales with white seams, shattered. 



Ca. Black flaggy shales, with (3) Monograptus gregarius, (2) Biplograptus 



vesiculosus, D. acuminatus, &c. 

 Bb. Pale non-fossiliferous mudstones. 

 Ba. Black slaty shales, (c) Zone of Pleurograptus linearis, (b) Zone of Bi- 



plograptus Clingani. (a) Zone of Climacograjptus Wilsoni. 

 A. Pale shales with hard grey and flinty ribs, non-fossiliferous. ///. Faults. 



Much of the ground within the glen is too complicated ever to be 

 perfectly mapped ; but the general arrangement of the rocks can 

 be easily made out. The disposition of the more important zones 

 is given in the accompanying plan and sections (Plan K, PI. XIII. ; 

 sections figs. 22, 23). 



Roughly speaking, the Moffat beds of the glen are arranged in 

 five subparallel anticlinal forms. 



The axis of the first fold crosses the stream- course obliquely 

 below the mineral spring. The lowest beds brought to the surface 

 are those of the Dicranograptus- Clingani zone of the Hartfell Shale. 

 To the south the strata of this anticlinal are faulted against the 

 greywackes of the south cliffs ; to the north they pass up into the 

 Birkhill Shales already described. 



The axis of the second or main anticlinal of the glen runs parallel 

 with the central portion of the bottom of the gorge from end to end. 



