DESCRIPTION OF THE PRINCIPAL EXPOSURES. 



8l 



A linear arrangement of the constituents, often accompanied 

 by banding of an imperfect kind, is well displayed on weathered 

 surfaces, and has been in some cases accentuated by slight crushing. 

 The direction of foliation is very constantly N. E. — S. W. with a 

 general dip of 50°-6o° to the S. E. The mass is crossed from edge 

 to edge by a dyke 50 yards wide of augite-diorite (diabase) with 

 micropegmatite. 



The scenery and physical features of the Shevaroys have been 

 described by Messrs. King and Foote, and in the Salem District 

 Manual by Mr. H. LeFanu. Like on many of these plateau masses 

 of the charnockite series the gentle slopes of the wide valleys facilitate 

 the artificial production of lakes of considerable dimensions. That 

 at Yercaud, and the hills in the neighbourhood, are shown in plate XII 

 which is the reproduction of a photograph taken from Arthur's Seat. 



Near the S.W. foot of the Shevaroys, and again between Salem 

 town and Kanjamalai, small, bare, rocky hills 

 stand up abruptly above the general level of 

 the plain. Some of these show clearly their lenticular structure, 

 and consist of masses'of basic garnetiferous members of the charnoc- 

 kite series. The rocks are comparatively coarse in grain and some- 

 times contain garnets as large as one's fist. As a rule the only signs 

 of foliation they show is an imperfect linear disposition of the con- 

 stituents parallel to the long axes of the lenses and to the foliation of 

 the gneisses around. Occasionally one comes across small E.N.E. dis- 

 locations in which a certain amount of mylonite is produced (see fig. 6) 



The Nagaramalai type. 



4-Stei.. 



Fig 6. Local twist wiih formation of mylonite in garnetiferous norite near 



Salem. 



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