286 C. LAPWORTH ON THE MOEEAT SERIES. 



The physical arrangement of the Moffat rocks of this locality will 

 be evident on a study of the accompanying plan (F) and sections. A 

 small cliff at the southern extremity of the section exhibits a syn- 

 clinal of Lower Hartfell Shale, broken by faults, but with its strata 

 little altered. The central portions of the trough are formed of the 

 hard flag-like black shales of the Dicranograptus zone, and afford 

 its characteristic fossils, Dicranograptus ramosus (Hall), D. Clingani 

 (Carr.). To the south beds of grey and black shale, with numerous 

 flinty ribs, are exposed in the bed of the stream, clearly passing 

 underneath the foregoing zone, and yielding in relief Climacograptus 

 Scharenbergi (Lapw.), C. Wilsoni, &c, the commonest fossils of the 

 lowest or Olimacograptus- Wilsoni zone of the Hartfell Shales. 



Fig. 19. — Qlenkiln Burn. (Lower Section, Black Linn.) 



Ba 2 . Flaggy black shales with Dicranograptus ramosus, Olimacograptus cauda- 



tus, &c. 

 Ba x . Black slaty shales with ribs of grey rock. Olimacograptus Wilsoni, &c. 

 A. Pale mudstones and dark shales with seams and beds of hard flagstone, 



much disturbed. 

 Aa. Pale shivery mudstones, contorted, non-fossiliferous. 

 Ab. Black shales with a few seams of grey flag. Ccenograptus gracilis, Thamno- 

 graptus, Bidymograptus, &c. ///. Faults. 



The northern side of the synclinal is inverted, and these beds 

 again emerge in that attitude from below the D.- Clingani zone in 

 the reverse order. 



They are in contact with a thick group of shivery shales and 

 mudstones, dull grey, brown, and black, with intercalated beds and 

 bands of hard siliceous rock, from an inch to a foot in thickness. 

 These beds are greatly faulted and broken, and are wholly destitute 

 of fossils throughout. At the foot of the small stream entering 

 from the northward they are followed abruptly by a thickness of 

 20 feet of black flaggy shales, crowded with fossils, principally 

 Ccenograptus gracilis (Hall), Ccenograptus surcularis (Hall), Tham- 

 nograptus tgpus (Hall). These fossiliferous beds are beautifully ex- 

 posed at the foot of the tributary stream, where they are seen to 

 contain some of the peculiar grey ribs already noticed. 



To the north-west they are succeeded by a great thickness of soft 

 grey, white, or brow^n shivery mudstones, barren of fossils, dipping 

 steadily up the little burn for nearly a hundred yards. 



On the south bank of the main stream the peculiar dark shales 

 and mudstones, with intercalated ribs of hard grey flagstone, fill up 

 the whole section between the fossiliferous zone above mentioned and 

 two contiguous bands of hard flaggy black shales, which are exposed 



