352 



LIETJT.-GEN. C. A. M c MAHON ON ROCKS OF [Aug. I 894, 



Pig. 1. — Specimen of metamorphosed tuff showing 'corduroy 

 structure.' 









HHBH^flSHHIHHHHHE 











f^--^" -<&**& iyr 





- ** ■ 



^^Jj 





v £ - ...; ■• \ .>.'■< '/' - •■; ■■ '^TS... 5 



[From a pliotograpb.] 



Collected in 1893. 



No. 37 



1230. Sp. 



Gr. 2-68. 



Bottom bed. 



„ 38 



J231. 



315. 



Next above No. 37. 



„ 39 



1232. 



2-85. 



., 38. 



„ 40 



1233. 



3-15. 



.. 39. 



„ 41 



1234. 



3-03. 



., 40. 



„ 42 



1235. 



2-65. 



„ ,, „ 41. 



„ 43 



1266. 



324. 



„ „ „ 42. 



Grass. 





Grass. 





No. 44 



.... 1267. „ 



2-87. 



Apparently in situ, about 2 o 

 3 feet above 43. 





Collected in 1892. 



No. 45 



1118. Sp. 



Gr. 2 69. 



Comes in adjoining No. 42. 



„ 46 



1119. 



327. 



„ ,. „ „ 38. 



„ 47 



1120. 



319. 



„ „ „ „ 39. 



Grass follows No. 44, and then at a distance of 20 yards the 

 epidiorite of Cock's Tor crops out apparently in situ. 



The hand-specimens of the above rocks are all compact, and vary 

 in colour from a yellowish to a greenish-grey. One, No. 41, appears 

 to be composed of two distinct layers : one of a greenish and the 

 other of a purplish tint. Some other hand-specimens, when examined 

 with a pocket-lens, are seen to have reddish felspathic streaks. The 

 fractured surface looks very much like a compact igneous rock. 



I now proceed to give the results of the examination of thin slices 

 of the above specimens under the microscope. 



