S.6oE. 



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



(7) Confirmatory Evidence from the more Northerly- 

 Portions of the Range. (Fig. 17.) 



The boundaries of the Archaean complex in the central and 

 northern portions of the range have been carefully mapped, and the 

 conclusion has been reached that, as in the south, the vs^estern 

 boundary is always a fault, sometimes vertical, and sometimes 

 reversed. A description of these portions of the range is reserved 

 for a future communication, but in view of the scarcity of exposures 

 of the junction with the Palseozoic Series in the south, 1 have 

 thought it well to give an example from the middle portion of the 

 range, which proves that, on the one hand, the Archaean Series has 

 been intensely folded, and that, on the other, it has undergone 

 powerful overthrust on to the Silurian rocks. 



Fig. 17. — Section of the range along the line of the Malvern Tunnel. 



f: 



Id c b \a bX 



[Scale: 4| inches^] mile.] 



rr=Railway-level. I e = Wenlock Shale, 



Jp^'i/"" — Fault between Trias | d = Woolhope Limestone. 



and Archaean. c = Tarannon Shales. 



i^i^=: Faults. I b = May Hill Sandstone. 



^=::Ereccia. a = Archaean. 



/= Trias. I 



The above figure represents a section drawn to scale across the 

 range, along the line of the Malvern Tunnel. The succession 

 of strata in the tunnel is taken from Symonds & Lambert's 

 description,^ in which measurements are given. The junction 

 of the Archaean with the May Hill and Triassic strata on the slope 

 of the hill has been fixed by careful mapping. 



It is clear from this section that the fault separating the Archaean 

 rocks from the May Hill Series has a very considerable hade 

 towards the eastern side of the hill. The angle of apparent dip 

 indicated by the line joining the point of outcrop at the surface 

 with that of intersection by the railway is about 57°. Making 

 allowance for the augle at which the railway cuts the dip of the 

 plane of junction, as deduced from its outcrop, I estimate the true 

 dip as being about 65° east, 7° south. That the junction really dips 

 eastward was noted by Symonds & Lambert,^ who state that the 



1 Quart. Journ. Geol. Soc vol. xvii (18G1) p. 152. ^ jbid. pp. 155, 157. 



