BY THE REV. J. MILNE CURRAN. 203 



Near Newbridge, the junction of the igneous and sedimentary- 

 rocks presents the same features. In a cutting on the Bathurst 

 side of the railway station bars of igneous and slate rocks can be 

 studied in actual contact. The boundary-line between the two is 

 still sharp, and no evidence can be found of a slate merging into 

 a granite. On the contrary, examples can be found where the 

 intrusion of the granite in a liquid or pasty condition, but 

 evidently under great pressure, has bent and crushed, and pushed 

 on one side, the easily yielding slates. In cases where the granite 

 does alter the rock with which it is in contact, the alteration 

 consists in the development of a rock not in any way resembling 

 a granite. Where the alteration is most complete, a hornfels is 

 the result, and where incipient alteration is noticeable, a close 

 examination reveals merely a rearrangement of old minerals and 

 the introduction of only one new one. Between Locksley and 

 Brewongle, on the railway line, a good example is exposed of 

 the alteration produced by the intrusion of granite. Near a high 

 level bridge, between these two stations, a mass of granite will be 

 found lying partly to one side and partly under a micaceous and 

 schistose rock. The granite sends veins into the overlying 

 beds. This upper rock, as stated, is of a schistose character, and 

 it will be noticed that the planes of schistosity are parallel to the 

 mass of the intrusive rock. In this instance the schistose planes 

 are horizontal, which gives the rock a bedded appearance. But in 

 other parts of the district, notably on the Hockley Road, south of 

 Peel, where a foliated or schistose structure is developed, the 

 foliation planes are vertical. This inclines one to the view that 

 an envelope of foliated rock once surrounded the granite mass, so 

 that when a portion of the original sediments remain above the 

 granite the schistose structure will be horizontal, but when they 

 are seen forming a vertical boundary to the intruded granite the 

 planes of schistosity will be vertical. In connection with this 

 peculiar structural development, it may be mentioned that a 

 schistose structure can be induced in wax and mixtures of oxide of 

 iron and pipeclay by pressure,* and that, in these instances, the 



* See Tyndall's " Fragments of Science," Vol. I. p. 366. 



