92 THE POIKILITIG PERIOD. CHAP. 



near Newent to Shrewsbury was displaced and disturbed; the 

 Malvern chain fronted a sea, perhaps a new sea, of waters on the 

 east : in these waters the red and white sandstones and conglo- 

 merates and marls which compose the Triassic or Poikilitic system 

 were deposited. All was sea to the east ; a large tract of land 

 existed to the west. The cause of this was a great fault on the 

 eastern face of the Malvern Hills, which depressed all the country 

 to the east. 



Geologists have gradually allowed themselves to be convinced 

 of the great truth, that the exterior parts of the earth have every- 

 where been subjected to rising and falling ; rising in one district, 

 sinking in another; almost every tract covered by the sea for a 

 long period, and then lifted above the general level to constitute 

 land, suffer degradation by rain, and give origin to rivers. 



Diagram XXIII. Sedimentary shore deposits. 



In the diagram above sketched, H may represent the sea-level, 

 above which, on the left, the land may be rising, as marked by 

 the upward arrow, and on the right the sea may be regarded as 

 sinking. In this case the land would be coming under conditions 

 of increasing waste, and the sea of acquiring fresh deposits on its 

 bed. These deposits would consist, usually, of pebbles, sand, and 

 clay ; and these three sorts of materials would be found not parallel, 

 but in something like the way represented in the diagram, where 

 p is a beach of pebbles lying in much inclined though irregular 

 layers against the shore; s a bank of sands drifted further; and 

 e the clay carried quite away from the shore, so as to slowly 

 settle in nearly parallel and generally almost horizontal sheets. 



In a general point of view, neither the depression of a tract 

 so as to become sea, nor the elevation of a tract so as to become 



