12 



HILLS AND VALES. 



CHAP. 



and of great antiquity. These rocks have been generally regarded 

 as of igneous origin, and at one time were thought to have been 

 erupted, after the stratified Silurian rocks were formed, which now 

 cover them in part. During my long examination of these hills 

 (18421844) I found this opinion untenable; and it has since been 

 agreed that the main part of the lowest rocks in all the hills of the 

 range is of older date than any of the strata resting upon them 

 unconformably. 



Now these later strata are of the Silurian and older than the 

 truly Silurian stages ; the grey sandstone of Holly bush and the black 

 shales of White-leaved oak (both near Eastnor and Ledbury) con- 

 tain Olenidge, Lingulidse, &c. of the series of rocks below the 

 Llandilo flags. 



Dr. Holl, on considering the metamorphic aspect of the funda- 

 mental Malvern rocks, and the undoubted great antiquity of the 



B 



Diagram IV. A. The gneissic rocks of Malvern. B. Cambrian strata. 



C. Upper Silurian strata. D. Old red strata. E. Permian and new red strata. 



earliest deposits which cover them, thinks there is ground for 

 referring these lowest rocks of Malvern to the Laurentian series 

 of Canada, the most ancient group of originally stratified deposits 

 which have yet been brought into the geological series. The 

 evidence is insufficient to establish this opinion ; but no geo- 

 logist will hesitate to admit the gneissic and other rocks of 

 North Malvern, at once crystallized and laminated, as belonging 

 to one of the earliest groups of rocks in the British Islands. 

 Some of the gneissic rocks of the North-western Highlands and 

 the Hebrides are shown by Murchison to be of equal if not 

 greater antiquity*. 



Siluria, ed. iv. p. 163. 



