86 Reports and Proceedings. 



Contortion of the strata is a common feature of the country, 

 affecting some of the newest Tertiary beds so as to place them in 

 a vertical position, and almost everywhere throwing the rocks into 

 folds, producing in many cases inversions of the strata. 



The author compares these rocks with those of the Simla area 

 described by Mr. Medlicott, who found there two strong uncon- 

 formities, namely, between his Siwalik and Nalum, and Nalum and 

 Subathu groups, and regarded the whole of the beds of the outer 

 Tertiary detrital zone from the base of the Subathu group upwards 

 as discordant to the Himalayan or Hill-series and to each other. 



The junction of the newer Tertiaries with the rocks forming the 

 higher hills of the outer Himalaya, both in the Simla area and in the 

 outer Punjab, is marked by disturbance, distortion, and inversion or 

 abnormal superposition in the Tertiary strata along the contact. 

 In the Upper Punjab the junction follows a curved line, running 

 nearljr east and west to the north of Eawul Pindee, then de- 

 scribing an angle which closely follows the great bend of the Jhilam 

 river near Mozufferabad, it runs more or less in a south-easterly 

 direction through Kashmere towards Simla. This junction line is 

 inseparably connected with the causation of the great mountain- 

 chains : it shows a parallelism to the axes of the outer ranges, and 

 is chiefly due to intensity of disturbance, the result of lateral 

 p)ressure. 



The author also refers to the difference existing between the 

 geology of the outer Himalayan region and that of the Salt Range, 

 as being similar to that which obtains between the Alpine and 

 extra-Alpine characters of European rock-groups, and suggests that 

 the recurrence of such similar features at such distances may indi- 

 cate a connexion between the former conditions of deposition and 

 the early history of the great chains themselves. 



Discussion. — Mr. Drew gave some further explanation of the author's views 

 and of the .geology of the district. 



The Chairman agreed with the author as to the analogy between the outer 

 ridges of the Himalayas and those of the Alps, and also as to the difficulty in such 

 cases of distinguishing between an inversion and a fault. From the different con- 

 ditions as to metamorphism of the Miocene and Eocene rocks in the Alps, he had 

 been led to question the fact of the inversion, and now found that most Swiss 

 geologists had come round to the opinion that the present position of the beds was 

 not due to mere inversion, but to actual dislocation. He thought this might also 

 prove to be the case in the Himalayas. 



2. " On the Mode of Occurrence of Diamonds in South Africa." 

 By E. J. Dunn, Esq. Communicated by Prof. Eamsay, F.R.S., 

 V.P.G.S. 



In this paper the author stated that the diamonds of South Africa 

 occur in peculiar circular areas, which he regards as "pipes," which 

 formerly constituted the connexion between molten matter below 

 and surface volcanos. The surrounding country consists of horizontal 

 shales, through which these pipes ascend nearly vertically, bending 

 upwards the edges of the shales at the contact. The rock occupying 

 these pipes was regarded by the author as probably Gabbro, al- 

 though in a very altered condition. Intercalated between the shale- 

 beds there are sheets of dolerite, etc., and dykes of the same rocks 



