274 H. J. JOHNSTON-LA VIS ON THE 



31. On the Teiassic Steata which are exposed in the Cliee- sections 

 near Sidmotjth, and a Note on the occueeence of an Ossiferous 

 Zone containing Bones of a Labybinthodon. By H. J. Johnston- 

 Lavis, Esq., E.G.S. (Bead March 22, 1876.) 



In describing the locality and geological position of the vertebrate 

 fossils which were obtained from the Triassic rocks near Sidmouth, 

 perhaps it would be as well to commence with a description of the 

 coast-sections for a short distance east and west of that town. 



Starting from the east, we find that the Marl* (which is the upper- 

 most subdivision of the Trias of South Devon) makes its appearance at 

 Branscomb Mouth, exposed beneath the Greensand and Chalk in the 

 cliff-sections, and in the ramifying valley cut through by the small 

 stream which runs out to sea at this point. It now forms the lower 

 portion of the cliff under Littlecomb Hill and Branscomb Hill, being 

 overlain by the Greensand and Chalk until it is exposed inland at 

 Weston Mouth by the action of the little stream called Weston 

 Water, which runs out here. 



It again forms the base of the cliff under Dunscomb Hill, being 

 still overlain by the Greensand and a small patch of Chalk; again it 

 is exposed and partly excavated by the little brook at Salcomb 

 Mouth ; thence it forms the base of the cliff under Salcomb Hill, 

 being now capped by the Greensand alone ; it is then largely exposed 

 on the surface in the valley of the river Sid. 



A f ew yards east of where the Sid runs into the sea, the Upper Sand- 

 stone (of Mr. Ussher) crops out, forming a cliff overhanging the Sid, and 

 constituting the bed of the stream for half a mile from its mouth, and 

 also tfie whole valley except where covered by gravel, which Mr. 

 Ussher tells me is in some places 15 feet thick, containing a bed of 

 peat about a foot in thickness. The gravel is chiefly composed of 

 chert, and contains teeth of Elephant, numerous specimens of which 

 have been found by Mr. P. 0. Hutchinson and others. 



To the west of Sidmouth, at the end of the Parade, we meet with 

 a low projecting cliff, called Chit Bock. Mr. Ussher, who has sur- 

 veyed this district, tells me he has met with no evidence of a fault 

 having existed in the valley; and therefore we may conclude that it 

 is the continuation of the small exposure of sandstone which is seen 

 to exist east of the river, as in section, fig. 1 (p. 276). At the western 

 end of the Chit Bock we find a fault which has given the Chit Rock an 

 upthrow of at least 40 feet ; but it is very possible it may be as much 

 as 80 feet, since it has no marl capping it, and in its lithological 

 character resembles the middle of the Upper Sandstone. We see, on 

 the western side of the fault, the Marl brought down within a short 

 distance of the beach, there being a small mass of Sandstone exposed 

 beneath it. All the Triassic beds from Branscomb up to the present 

 place dip gently to the east ; but now we find them dipping to the 

 west ; this only takes place for the distance of about half a mile ; 



* See Ussher, • Geological Magazine,' Decade II. vol. ii. No. 4, April 1875. 



