436 Topley — Physical Geography of East Yorkshire, 



west. It is composed of Permian and New Eed strata thickly 

 ■ covered with Boulder-clay and gravel. The secondary beds on 

 the east crop out in a series of escarpments ; their scarped edges 

 being presented towards the north and west, while the gentler 

 slope, or " dip slope," falls towards the soLith and east. The chalk, 

 as the highest secondary bed, occupies the south-eastern corner, 

 ajid. rising as a bold escarpment from the Yale of Pickering (Speeton 

 and Kimmeridge clays), sweeps round to the west and south, over- 

 looking the Yale of York. The Lower Secondary beds rise from 

 beneath the Chalk, their scarped faces likewise facing northwards. 

 These owing to a great unconformity, do not pass south parallel to 

 the Chalk. The escai-pment of the Lias however is almost con- 

 tinuous from the Tees to the Humber. 



The scarped hills of Cleveland (Lias capped by Inferior Oolite) 

 are highly picturesque. The Oolitic cappiag weathers into a steep 

 face overlooking a more gentle slope of Lias shale. The bare rugged 

 top of Eosebury Topping and the top of the escarpment seen south- 

 west from Guisboro' are examples of precipitous Oolitic ^ cappings. 



These escarpments, in common with all analogous hills in England, 

 have this striking character. The same bed, or its representative, 

 crops out at about the same height of the escarpment all along its 

 course. Thus, in th-e North Cleveland hills, the " Ironstone and 

 Marlstone series" crop out some way down the side, and the hills 

 are capped by the same bed of Sandstone (Inf. Oolite). In other 

 words, these escarpments run along the strike and their scarped sides 

 face the dip. Thus, if the beds are dipping to the south the scarped 

 side will face the north, and the escarpment will run east and west. 

 Now, how can this fact be accounted for if these -escarpments are old 

 sea cliffe ? To kam what a Lias sea cliff is like we have only to 

 examine the present coast line of Cleveland. Here the beds are seen 

 to dip in the cliff section, and therefore the cliff is not formed along 

 the strike. Moreover beds are seen to dip one under the other and 

 disappear, so that a cliff section at one place may give a set of beds 

 quite different from another section taken a few miles off. Thus, on 

 the Yorkshire coast, we ]3ass in the same line of cliffs from Lias in 

 the north, through all the Oolitic series in succession, to Chalk in the 

 south.^ Such is never the case with an inland escarpment. This 

 presents the same set of beds throughout its entire length. Now, 

 since " escarpments " run along the strike, whilst the present sea cliffs 

 rarely or never do, it would seem that we must no longer look to 

 marine action as the mode of formation of these escarpments. They 

 are assuredly not " river-cliffs," since rivers by no means always 

 run parallel to them or even near them. There remains then only 

 pure subaerial agencies to account for them. This subject has 

 already been written u^Don by Mr. Jukes,^ Prof Eamsay,* Mr. Greikie,^ 



•J The Inferior Oolite here is a Calcareous Sandstone. (" Dogger.") 



2 This is well shown in the coast section appended to Prof. Phillips' " Geology of 

 Yorkshire." Vol. I. 



3 On the River Valleys of the South of Ireland. Quart. Journ. Geo!. Soc. Vol. 

 xviii. (1862.) p. 378. 



^ Phys. Geog. and Geology of Great Britain. 2nd Ed. 1865, p. 81 et seq. 

 s Scenery and Geology of Scotland. 1865. p. 138. 



