TRANSACTIONS OF SECTION C. 613 



than now. Subsequently depression took place, but towards the close of that 

 period elevation again set in, and the terraces at Ssebo and others below the 

 Eidfjordsvand are the result of this last elevation. 



4. The Evidence of the Hydrothermal Metamorphism of the Schists of 

 South Devon. By A. R. Hunt, F.G.S. 



The author contends that a dominant cause of alteration in the Devonshire 

 schists was the presence of water ; in other words, that as the presence of some 

 degree of heat is not disputed the metamorphism was hydrothermal. 



He divides the schists into two groups : — 



1. Rocks which have been variously called chlorite-schists, hornblende-schists, 

 epidote-schists — or, generally, green rocks. 



2. Mica-schists, more or less associated with quartz-schists. 



The schists of the first group are, he observes, usually attributed to the altera- 

 tion of basic augitic rock ; they were originally composed of anhydrous minerals, 

 pyroxenes, and felspars. 



Evidence is adduced to show that they now have become transformed into 

 rock, consisting of amphibole, epidote, zoisite, and chlorite ; the three last of 

 these contain water of crystallisation, together with albite, which in these rocks 

 is occasionally charged with actual water. In short, he remarks that the one 

 characteristic substance which by way of addition distinguishes the green rocks 

 from their assumed parents is water. 



He then deals with the second group, showing a similar result. 



Thus, he maintains, the hydro-metamorphism of the district seems pretty well 

 established, and contends that whilst thermo -dynamic metamorphism is admitted 

 in South Devon, the universal presence of water in the newly constituted rocks 

 compels ns to assign a very important position to hydro-metamorphism as an 

 agent of change. It is not so much that water must have been present during 

 the metamorphic process, as that it is in the rocks now, and could not have been 

 introduced since their crystallisation. 



5. Note on the Scenery of Ceylon. 

 By A. K. CoomAraswImy, B.Sc, F.L.S., F.G.S. 



It is probable that Ceylon has been exposed to continuous denudation since 

 very early Palaeozoic times. The foliation of the crystalline rocks has had a 

 marked influence in determining the directions of the river valleys and the 

 general condguration of the country. The foliation strike is usually from N. to 

 N.W. Many rivers have a similar direction, as examination of a map will show. 

 A north-and-south strike-valley runs from Wattegama to Dambulla, followed by 

 the railway as far as Matale. N.N.W. valleys are conspicuous N. of Htinasgiriya. 

 The Mahaweli Ganga valley, south of Peradeniya, is a strike-valley ; another good 

 example is the valley running N.W. from Hatton. Each of these valleys is 

 followed by the railway. Other conspicuous N.W. valleys (probably strike- 

 valleys) are those between Kurunegala and Matale ; and N.E. of Adam's Peak 

 and S. of Eatnapura. A small area east of Kandy has been examined in detail, 

 and shows a diagrammatic system of strike-valleys, with others at right angles 

 thereto, the strike being here, however, more nearly east and west than is usually 

 the case. The bands of limestone may have had some eflect in determining the 

 actual positions of these valleys. Of course all valleys in Ceylon are not strike- 

 valleys ; thus the Mahaweli Ganga valley crosses the general strike below 

 Gettembe (E. of Peradeniya), forming a series of rapids. 



A characteristic feature of the scenery of Ceylon in many parts is its precipitous 

 character ; the seemingly ' bedded ' granulites form mural escarpments and dip 

 slopes, as if they were a series of sedimentary rocks. 



