SERIES OF THE DEVON COAST-SECTION. 151 



seen in veins, none apparently more than from 1" to 2" thick. There 

 seems to be an entire absence of massive beds of anhydrite, such as 

 occiir at Newark and elsewhere in the Midlands ; but the relation 

 of the gypsiferous beds to the green marls is the same. 



In this cliff- section to the east of Sid mouth we have the most 

 complete development of the normal Keuper formation of the Mid- 

 lands. I saw no trace of the Khsetic formation (properly so called) 

 as represented in this country by the Avicula-contorta shales*. 

 The pale-green marls here as elsewhere t cannot -be separated on 

 physical or stratigraphical grounds from the Keuper, of which they 

 form the uppermost portion, though for purposes of mapping it may 

 be convenient to include them in the " Penarth Series." 



Beneath the Upper Greensand beds which cap the hills between 

 Salcombe and Weston Dingles, the pale green marls are developed 

 in such force as to mark the uppermost horizon of the Keuper. 

 Owing to their inaccessibility on the face of the cliff, I could not 

 determine their actual thickness above the highest red-marl bed, 

 nor could I ascertain to what extent they may have been disguised 

 by the down-wash of material from the Upper Greensand beds above. 

 Estimating the thickness of the Keuper exposed in this portion of 

 the cliff at 300 feet, and adding to this another 100 feet for the 

 beds which crop out in the cliff below them to the west and above 

 the calcareous series, we get about 400 feet of marls in which 

 marked beds of sandstone seem to be of rare occurrence t. This, for 

 some reasons, we might take as the approximate thickness of the 

 Upper Keuper here ; or, if we include in this division the 150 feet 

 of beds marked by the prevalence of calcareous concretions, we get 

 550 feet. Then the Lower Keuper series of massive sandstones and 

 red and variegated marls gives us another 60 feet. We thus get 

 an estimate of 610 feet for the Keuper as against the 1350 feet 

 estimated by Mr. Ussher § ; or, if we allow, say, 50 feet for removal 

 by denudation of pale-green marls at the top, an outside estimate 

 of 660 feet. There is very little faulting in this part of the cliff ; 

 two small faults with an aggregate downthrow to the east of about 

 15 feet are cancelled by an apparent fault with a downthrow to the 

 west of from 15 to 20 feet at Salcombe Dingle. The red marls at 

 Seaton, which I examined about four years ago, I take to be a repe- 

 tition of the beds in the middle part of the cliff between Salcombe 

 Dingle and Branscombe Mouth, by the faulting which has let down 

 the Chalk at Beer Head, just as in the beds east of the Sid those 

 in the Peak and High Peak hiUs are repeated by the faulting at 

 Sidmouth. 



* By this is intended the series of paper-shales and tliin-bedded sandstones, 

 marked by the occurrence of the " bone-bed," of Cardiu^n rhcstmom, Feden 

 valoniensis, Avicula contorta, and PuUdstra arenicola. 



t E. g. at Newark and Edwalton (Notts), and in the Garden Cliff at AVest- 

 bury-on-Severn. 



\ I saw on the beach a solitary block of ripple-marked sandstone, to tlie 

 great abundance of which in the Upper K^euper of Notts I have previously 

 drawn attention (Quart. Journ. Geol. Soc. November 1876, p. 515). 



§ Log. cit. p. 392. 



