148 PROF. T. T. GROOM ON THE GEOLOGICAL [May 1 899, 



the intrusive masses is best explained by a fault. The two main 

 dykes running down the adjacent slopes are not coiitinuous across 

 the depression, as was apparently supposed by Phillips/ for mapping 

 shows that neither passes beyond the bed of the stream. The 

 very different dip and strike of the two necessitates the conclusion 

 that the dykes do not even meet one another, and that in fact 

 the ends of two different dykes are brought into proximity along a 

 transverse line of faulting. 



The same fault would appear to form the southern boundary of 

 the strip of sandstone east of that which contains the igneous rocks 

 at the south-western corner of Midsummer Hill, for the dip of the 

 sandstone here is different from that on the southern side of the 

 stream. A continuation of the same line of faulting towards the 

 west-south-west would coincide with the northern boundary of the 

 patch of May Hill rocks near i'owlet Farm, to which allusion 

 will be made later, and also with that of the Black Shales on the 

 west of this patch. 



It is difficult to say whether the great axial line of dislocation 

 has been displaced by this fault or not; but, judging by the probable 

 distribution of the rocks concerned, as indicated by the relief of the 

 surface, a certain amount of displacement has occurred. I could 

 detect no traces of the May Hill Beds on the northern slope of 

 liaggedstone Hill : the position that they might be expected to 

 occupy, were there no transverse faults, would, indeed, seem to be 

 taken up on the southern side of the Pass by a small mass of 

 Archaean rocks. 



The fault is probably one along which varied differential move- 

 ments of the blocks concerned have taken place, for no simple 

 movement would appear to be capable of bringing about the 

 observed relations of the rock-masses. 



(5) The Gullet Pass. 



The Gullet, or line of depression between Midsummer and Swin- 

 yard Hills, as already pointed out (p. 140), is a line of dislocation. 

 Against this fault end the four faults bounding the Archaean blocks 

 on the north and south. It is in part, at any rate, of post-Triassic 

 age, for it has dislocated the great fault by which the Triassic 

 rocks have been thrown down on the eastern side of the range (see 

 map, PI. XIII). 



(6) Chase End Hill. (Fig. 16.) 



The structure of this southernmost portion of the Malvern range 

 is simpler than that of the hills already considered. The hill is 

 somewhat lanceolate in plan, and its axis meets that of the southern 

 part of Raggedstone Hill at about a right-angle. 



The greater part of Chase End Hill is formed by an elongated 

 elliptical mass of schistose and gneissic rocks. Near the north- 



1 Mem. Geo]. iSurv. vol. ii (1848) pt. i, p. 53. 



