362 Mr. H. E. Strickland on the Elevatory Forces 



(averaging half a mile) approximately represents the thickness of 

 the upper or solid portion of the plutonic rock. Such I assume 

 to have been the condition of things when that great elevatoiy 

 movement commenced which upheaved the westernmost side of 

 our island. It is irrelevant here to inquire whether this general 

 upheaval was effected by the mere expansion caused by increased 

 temperature, or by the introduction from other quarters of vast 

 masses of fluid matter beneath the elevated area. It will be suf- 

 ficient to admit that a special volcanic focus existed beneath the 

 syenitic axis of Malvern, and that its energies were called into 

 action simultaneously with the more general movement which 

 elevated the area of Herefordshire and Wales. 



We may now suppose that the elevatoi-y forces beneath the 

 Cambrian region had accumulated so as to overcome the super- 

 incumbent weight ; while the region to the eastward, either from 

 its greater rigidity, or from the less amount of subjacent force, 

 remained in a quiescent state. A separation would now take 

 place between these two areas ; a long and sinuous line of frac- 

 tm-e would divide them ; and the region where Force had over- 

 come Resistance would begin to rise higher and higher above the 

 area which remained unmoved. 



The previous elevatory movement which has been shown to 

 have existed along the Malvern axis probably rendered this a 

 weak point in the earth^s cnist, and caused the line of fracture 

 to coincide with that axis. As soon as one side of this line 

 began to rise and a fault to be produced, the volcanic forces 

 which had been pent up beneath the syenitic axis would now 

 find, or endeavour to find, a vent. Struggling to escape along 

 the line of fault, they would thrust up the solid syenite above 

 them, raising it into a lofty cliff above the downcast area, and 

 elevating, overturning, or crumpling up the edges of the Silu- 

 rian, Devonian, and Carboniferous strata which rested upon it. 

 (See Plate I.) 



In the above diagram I have taken as a basis the section across 

 the Worcestershire Beacon published by the Geological SuiTcy, 

 and have endeavoured to supply conjccturally those portions of 

 the strata which have been removed by denudation, or which lie 

 too deep to be visible. I have supposed that a vast mass of 

 Devonian and Carboniferous rocks has been upheaved bodily, 

 while the lower strata nearer the syenite are more or less frac- 

 tured, crushed and contorted. The thickness of the strata which 

 have been since denuded may appear enormous ; but it is founded 

 on the careful measurements of the Geological Survey, which 

 give about 5500 feet for the Old Red Sandstone of Hereford- 

 shii'e, and 3500 for the incumbent Carboniferous series at the 

 nearest point (Dean Forest), where the undulations of the beda 



