6 TRAPS AKU INTERTRAPPEAN BEDS 



Another equally characteristic rock, though less abundant, is a 

 peculiar porphyritic basalt, containing numerous tabular crystals of glassy 

 felspar, often greenish in colour, and measuring usually from ^ inch to 2 

 inches across. 



Both these forms of rock have been pointed out by other observers, 

 and especially by Dr. Carter and Colonel Sykes, but they are so pe- 

 culiarly characteristic of the Deccan traps that they wUl bear referring 

 to again. It was by means of their occurrence that I was enabled to 

 recoo-nise immediately the traps of Cutch as belonging to the same series 

 as that of the Deccan and Malwa. 



4. Occurrence of volcanic ash. — There is one peculiarity of this 

 series, however, which has not been before, I think, clearly pointed 

 out, and that is the frequent occurrence throughout of beds of 

 volcanic ash. The beds have, it is true, been noticed and well 

 described by Malcolmson* and Carterf, under the name of basaltic 

 breccia, or volcanic breccia, but both these writers looked upon the 

 rock as intrusive. This, I feel convinced, is an error; the rocks in 

 question are so precisely similar to those formed of the ejecta showered 

 forth from volcanoes during eruption, and which constitute the greater 

 portion of the cone of most large recent and extinct volcanoes, that 

 I have no hesitation in considering them as identical. 



In some places, no inconsiderable proportion of the whole series is 

 formed of this rock. Several beds may be seen in the cuttings upon the 

 sides of the hill ranges traversed by the road between Poona and 

 Mahableshwar, especially at the Kamatki Ghat. One bed is peculiarly 



* Trans. Geol. Soc, Bombay, Vol. VI, p. 372, note. 



t Geology of the Island of Bombay, Jour. Bombay Br. Roy. As. See., Vol. IV, 

 pp. 164, 195. Summary of the Geology of India, id. Vol. V, p. 2S7. See also Vol. VI, 

 p. 171. &c 



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