164 W. A. K Ussher — Subdivisions of the Trias. 



at Tiverton in the summer of 1872, as are displayed, with local 

 variations, in the south coast. A rough examination of the latter 

 in the spring of 1873, in company with my friend and colleague, 

 Mr. H. B. Woodward, fully substantiated the lithological divisions 

 I had been enabled to make inland, and showed us the true nature 

 of several members, the absence of which had been accounted for by 

 local impersistency or gradual and even abrupt transition. The 

 additional light thrown upon the subject by the South Devon 

 coast, showed the presence of numerous faults, cutting out, and 

 displacing the divisions, which, aided by a practical acquaintance 

 with most of the lithological variations the beds assume, enabled me 

 to account for many enigmatical districts in my former work, to 

 trace many faults with comparative certainty, and led to the per- 

 sumption, that in a few local instances, between Watchet and the 

 South Coast of Devon, in which the lowest division is either alto- 

 gether unrepresented, or very feebly so, its absence may be accounted 

 for by the overlap of the overlying member, or by its total or partial 

 elimination by faults. In the spring of 1874, the establishment of 

 the same general sequence, as exposed on the south coast, in the 

 Watchet district, by Mr. Woodward and myself, and the consequent 

 corroboration of my views by him, has enabled me to state the re- 

 sults arrived at, with much less diffidence than my own unsupported 

 testimony would allow. For the publication of this resume, in anti- 

 cipation of the Survey Memoir on the district, in which all details 

 will be given, I am indebted to the kindness and consideration of the 

 Director of the Geological Survey of England and Wales. 



As we cannot go into details at present, the subjoined table of the 

 divisions made, and a brief allusion therein to the more important 

 lithological varieties they assume, supplemented by a very short 

 account of each division, will be sufficient to set forth the skeleton 

 of our facts. The beds are given in descending order. 



1. — Eed Variegated Marls, calcareous above, loamy in lower beds, 

 locally containing veins of gypsum. 1 



2. — Eed, buff, grey sandstones and rock-sand, containing cal- 

 careous nodules, and thin impersistent bands and pockets of dark 

 red clay. Lenticular masses of sandy marl and beds of the same 

 were locally shown near their junction with the overlying marls. 

 In some localities the sandstones become very calcareous ; in others 

 they ai'e mottled. 



3. — Pebble beds of the Devon Coast, large ellipsoidal pebbles of 

 quartzite with impersistent beds of sand, in a matrix of red sand. 

 Pebble beds of Buriescombe, pebbles mostly small and round, of 

 quartz and grit, the former predominating. Conglomerate, containing 

 pebbles and subangular fragments of limestone, grit, and quartz, of 

 various sizes, in sandstone matrix, generally thick-bedded. 



1 Since this paper was sent to press, Mr. P. 0. Hutchinson, of Sidmouth, informed 

 me that the occurrence of pseudomorphous crystals of rock-salt had been noticed by 

 Mr. Onnerod and himself in the Upper Marls, near Salconibe Mouth ; I have since 

 obtained a few specimens from that locality, and also, in descending the cliffs at "Wind 

 Gap, between High Peak and Peak Hills, west of Sidmouth, was very fortunate m 

 obtaining numerous slabs exhibiting well-marked pseudomorphs and ripple-markings. 



