156 EEY. A. IRTING Olf THE HED-EOCK 



and disintegration of these marls has furnished the numerous 

 indurated fragments of precisely similar marl which are found (as 

 described above) throughout the series of beds which I have 

 ventured to identify as the Bunter; and it would be difficult to 

 deny that it is to these marls that we may look for the finer 

 marly detritus which constitutes the material of the intercalated 

 (often lenticular) marly bands of that formation in Devon as in the 

 Midlands. 



At the base of the Salterton pebble-bed we have, I believe, direct 

 evidence of a physical break in the series. It may be summarized 

 thus : — 



(a) StratigrapJiical. — Not very direct or conclusive. Taking the 

 sandstone-beds as indicating the dip of the pebble-bed as a whole, a 

 careful measurement gave a dip 4° IS'.N.E. An equally careful 

 measurement of the dip of the underlying marls along the line of 

 one of the even pale-grey bands, where the marls first appear from 

 beneath the pebble-bed on the shore, gave a dip 5° N".iSr.E. Half a 

 mile west of Budleigh Salterton is a fine gorge in which the horizontal 

 strike of the pebble-bed is seen running due J^. and S. ; the dip noted 

 above must be therefore very nearly the true dip of the pebble- 

 bed. There is a considerable discordancy of dip among the marl- 

 beds themselves, so that it is not easy to say what the general dip 

 of that formation may be. Beyond the gorge just mentioned both 

 they and the pebble-bed are nearly horizontal in the upper part of 

 the cliff ; and west of the coastguard station I measured the dip of 

 the marls and found it nil on both the converging sides of a cove 

 about 300 feet above the shore. 



(b) Physical. — This I consider to be strong, (i.) The pebble-bed 

 at Budleigh Salterton lies on an eroded surface of the marls. This 

 is not always seen on the cliff-face, owing to the lodgment of fallen 

 debris from the pebble-bed above on the projecting ledge formed by 

 the more coherent marls ; but at and near the easternmost portion, 

 where the loose debris is swept away by the waves, it is very clear 

 (see diagram, p. 155). At the eastern end I found a surface of 

 several square yards, showing erosion into a wave-like form, exactly 

 as in the Eeading Clays {e. g.) beneath the quaternary gravels. 

 This surface tvas coated over with a limonitic ]paste.^ which followed the 

 inequalities of the surface^ and jiUed up the interstices between the 

 pebbles above, sometimes for as much as a foot or more. It is 

 undoubtedly a deposit by infiltration through the pebble-bed. At one 

 place a layer of reconstructed marl was seen about two yards up in the 

 pebble-bed — evidence, as I take it, of contemporaneous denudation of 

 these marls. The erosion of the marls at the base of the pebble-bed 

 may be seen by the side of the footpath up the gorge, (ii.) There is 

 no trace whatever of a passage. The Eed Marls (an indurated silt 

 of the finest powder) give place suddenly and abruptly (without any 

 sign whatever of approaching change in the marls) to a deposit of 

 the coarsest roUed detritus, as strongly current-bedded as any I ever 

 saw. The change is in fact such as can only be explained by pre- 

 vious induration and planing-off of the marls, contemporaneously 



