150 EEV. A. IKYINGr ON THE RED-EOCK 



to them, and increasing in importance as we ascend the series, 

 proper Keuper marls occur, mostly brown-red, but variegated with 

 pale-grey layers and irregular patches. The first important marl- 

 bed is from 10 to 12 feet thick. The sandstone bed next above this 

 is 10 feet thick. In some of these marls there are included weU- 

 roUed blocks of an older marl, the parent rock of which we shall 

 perhaps be able to identify as we proceed. 



(3) Xext, in ascending order, comes on, by a gradual transition, 

 a series in which marls predominate, the sandstones (although pretty 

 persistent) being much more fully developed and quite subordinated 

 to the marl-beds. These marls occur in very massive, well differen- 

 tiated beds, with little or no lamination, very hard and tough, spKt- 

 ting on the face of the cHff in a rude prismatic and subcuboidal 

 fashion, the fallen masses weathering subsphericaUy. In the more 

 fine-grained and compact varieties, where masses have been split off 

 by frost action, the rock shows what one must be allowed to caU 

 " conchoidal " combined with " splintery fracture " on a large scale. 

 This character of the beds is maintained through a vertical range of 

 about 150 feet. Throughout this range the marls are characterized 

 by the presence of numerous calcareous concretions *, many of these 

 being geodes lined with crystals of calcite. I saw one rock mass on 

 the shore, partly buried in shingle, of a decided tufaceous character ; 

 but this I regard as the result of deposition from the calcareous 

 springs which escape from these beds on the cliff-face. Hegular 

 layers of the concretions described (like the layers of flints in the 

 UXDper Chalk) run through the more compact marls in parallel lines 

 of bedding. 



Passing from east to west (i. e. towards Sidmouth), the concre- 

 tionary masses first crop out on the cliff-face about ^ mile west 

 of Salcombe Dingle, in a bed of rather sandy marl about 2 feet 

 thick. From the pale-grey colour of this bed, it marks a very defi- 

 nite horizon, which can be followed with the eye all along the face 

 of the cliff as it rises to the west, until it is cut off on the hill-flank. 

 This gives us a very good upward limit for the concretionary cal- 

 careous series. So far as I could see, aU. the beds above this are 

 more uniformly marly and devoid of these concretions. 



(1) East of Salcombe Dingle the marls become gypsiferous for 

 about 150 feet ; and as they are continued upwards subordinate 

 beds of pale green marls begin to appear. These become more pro- 

 nounced higher up the cliff, until at last they supersede the deep 

 red marls altogether. These pale-green marls were examined in 

 numerous fallen blocks at the foot of the chff, weathering sub- 

 cuboidal (occasionally shaly). Traces of pseudomorphs after sodium- 

 chloride crystals were noted, but time did not permit a thorough search 

 for these. They are probably soon obhterated by the attrition of sand 

 and shingle driven by the waves at high tides. The gypsum is only 



* An analysis of tlie more compact portion of one of these nodules in my 

 laboi-atory failed to detect any trace of magnesia. A further quantitative ana- 

 lysis gave 11-01 per cent, of carbonate of lime, and I'Ol per cent, of Fc^Og. 

 The residue was for the most part a fine earthy powder, very Kttle sand. 



