Professor T. Groom — The Martley Qiiartzite. 



563 



of this fact would be that we have here a quartzite interstratified 

 with rocks of the Malvernian Series. 



Mr. Coles suggests that the apparent relation seen here is " not the 

 real one." If by this be meant not the original one, I am quite in 

 accordance with him. Quartzites certainly occur on a limited scale 

 interfoliated with gneissic and schistose rocks in the Malvern Hills, 

 but they are of quite a different type to that seen at Martley, being, 

 in fact, quartz-schists representing, according to Dr. Callaway, the 

 extreme metamorphism of felsites and gneissoid quartzites produced 

 from diorites. 



The Martley quartzite, on the other hand, as Mr. Coles shows, 

 and as my own investigations prove, is *a typical sedimentary rock, 

 with a microscopic structure essentially similar to that of the 

 Cambrian quartzite of the Malvern Hills. 



I have already maintained ' that in the Malvern area the 

 Malvernian Series is sometimes thrust on to the Cambrian beds. 



l^OcfS 



Fig. 1. — Section in the Gravel Pit near Martley. 

 D. Diorite. 

 S. Schists. 

 Q,. Quartzite. 

 d. Detritus. 

 Length aJ= 9 ft. 6 in. 



if[,uS 



Fig. 2. — Ground-plan of same (diagrammatic) . The dotted lines indicate roughly 

 the probable limits of the outcrop of the quartzite on a surface at the level ol th© 

 floor of the pit. 



1 Ann. Rep. Brit. Assoc, 1898. 



