﻿Correspondence — Rev. 0. Fisher ; S.E.R., Reversed Faults. 527 



Adelaide chain of metamorpliic and slate rocks, where they are 

 covered up by a Pliocene drift (of pluvial or glacial origin), contain- 

 ing remains of extinct marsupialia and trees only. 



The two sets of deposits are shown in the Well-section alluded to, 

 which is as follows : — 



Estimated thicknesses. 



Pliocene — Feet. 



"Mallee"clay 40 



Miocene (marine). 



Light-coloured sandstone with casts of shells 10 



Gravelly ironstone and bands of clay) „, 



Blue marl j 



Sandstone without shells 17 



Loose sand 6 



Actual depth 154 



University of Adelaide, 



June IMi, 1877. Ealph TatE. 



ELEPHAS MERIDIONALIS IN DORSET. 



SiK, — At a recent visit to the Blacbmore Museum at Salisbury, 

 I was surprised to see two specimens of the teeth of Elephas 

 meridionalis, which were labelled as found at Dewlish, in Dorset- 

 shire. This being a preglacial species, it would be interesting to 

 learn under what conditions they occurred at that locality, which is 

 situated among the Chalk downs. The specimens were white, and 

 had the appearance of having come out of Chalk debris. 



The only specimen I have seen from any English locality besides 

 the Cromer Forest-bed was a fragment at the Chichester Museum, 

 said to have been found on the neighbouring Sussex coast. 



Can any of your correspondents give information about these 

 specimens ? 0. Fisher. 



EEVERSED FAULTS IN BEDDED SLATES. 



Sir, — I should like to call Mr. Hebert's attention to a few points 

 in his article on the above subject in the October Number, which 

 appear to require further consideration. Though it may be the 

 established rule in some coal-mining districts that the hade of a 

 fault is to the downthrow, there are in other districts exceptions to 

 this rule, in which the faults are 'reversed,' or, as they are commonly 

 called here, overlap faults. The cause of these reversed faults is, as 

 stated, no doubt horizontal pressure, the results produced varying 

 with the angle of hade, friction, and so forth. The causes of these 

 horizontal pressures I should be glad to see further discussed by the 

 author. The cooling of the earth, and consequent contraction of 

 the nucleus beneath the solid crust, has, as well as the more local 

 effects of earthquakes and volcanic intrusions, been suggested as a 

 cause. It is evident that a local subsidence under an arched portion 

 of strata will, if the abutments are stronger than the arch at the 

 line of subsequent rupture (or fault), cause an overlap or reversed 

 fault when the arch gives way, or it is evident that the matter may 



