62 THE RIDGWAY FAULT. 



south-west for a short distance ; thence it extends in a direction 

 almost due north. Here we find the Kimmeridge clay brought 

 against the base of the chalk escarpment ; whilst at Ablx>tsbury 

 the Oxford clay is brought against the grcensand, it (the greensand) 

 resting on clay, and the two beds are themselves horizontal. Such 

 are the leading characters of the Ridgway Fault. Its existence, 

 and the sections quoted, cannot, I believe, in many places be 

 directly traced, since the railway cuttings have become much over- 

 grown with grass, and have obliterated some of the best sections. 

 But in the days when the line was cut and the tunnel bored, some 

 highly interesting facts must have been disclosed for the geologist. 

 Now we are able to infer the existence of the dislocation to 

 a large extent by the anomalous position of the beds disclosed by 

 any quarries, gravel pits, ditches, and roadside sections which may 

 occur. 



Remarkable as the Ridgway Fault may appear to be, both from 

 the extent of country which it tiaverses and the magnitude of the 

 dislocations occasioned by it, it is rendered the more important from 

 the discovery by the Rev. Osmond Fisher of the cross fault, which 

 cuts the former almost at right angles, running in a north and 

 south direction up the valley by the side of the Weymouth and 

 Bridport Road. On the east side of this Mr. Fisher tells me he 

 found the Purbeck beds dipping northwards against the highly 

 inclined chalk, and on the west side the Purbeck beds rise to the 

 noith against the chalk, which dips at a high angle towards the 

 north. This fault, he says, runs towards Charminster, bringing the 

 Eocene beds against Maiden Castle and throwing out springs about 

 "NVhitwell, and forming the valley running towards Cerne. 



Mr. Osmond Fisher made a further discovery in connection with 

 this fault which, perhaps, is the most curious and singular feature 

 of all. It was owing to the construction of the railway between 

 "VVeymouth and Dorchester, and the trial shafts which were sunk 

 for the tunnel, that excellent sections were exposed, and, 

 fortunately, an experienced observer was on the spot to watch them. 

 The account, with diagrams of the section, were published in a 



