1838.] 



Ne-elgherries and Koondahs. 



235 



The plains of Malabar offered another striking spectacle, there were 

 numerous fires scattered over all their extent, which I was told were 

 meant to keep wild beasts aloof j these lights, diminishing in size as 

 they receded farther, at last looked like stars, and it became difficult to 

 distinguish where the terrestrial lights finished, and where those of the 

 firmament began. 



I must be permitted, before concluding this account of the Koondahs, 

 to add a few words on the controversy among geologists, regarding 

 the insensible passage of granite into basalt ; particularly after having 

 minutely examined this place, which appears to me the most desirable 

 for such an enquiry, as we see the two rocks, not only associated, but 

 mixed together and entangled the one in the other ; and, if truly such 

 a metamorphosis exists between the two rocks, it ought to be seen here. 



We have seen that in this group basalt traverses and caps granite, 

 having burst from below upwards ; therefore it must have appeared on 

 the surface of our planet posterior to the granite, and these two rocks 

 cannot, at any rate, be contemporaneous. It has been inferred, because, in 

 one or two localities, these two rocks appeared to pass insensibly one 

 into the other, that they have the same origin, nature and composition, 

 differing only in appearance on account of some adventitious circum- 

 stances, and because the one has been erupted before the other. With- 

 out entering deep into the question, which would carry us beyond the 

 purpose and limits of this essay, I will only state what my observations 

 have been in the examination of the two rocks in the Koondahs, where, 

 on account of their intimate mixture, if such an insensible transition 

 existed, it ought to be a common occurrence. The only thing I observ- 

 ed, in very few places, was a mixture of the tw 7 o rocks at the points of 

 contact, and which, after all, extended but a few lines, or, at most, an 

 inch or two, on both sides, after which the rocks resumed their respec- 

 tive composition. But even this kind of mixed rock was very rare, 

 and only when the basalt traversed greenstone, or sienitic granite, or 

 hornblende slate ; and, for one instance of this kind, I saw a hundred 

 in which the line of demarcation was decided and plainly seen. I sus- 

 pect that the phenomenon, observed by Dr. Hibbert and Dr. Maccul- 

 loch, was nothing more than what every geologist sees daily in India, 

 namely the passage of the large grained, laminar, primitive greenstone, 

 into the finegrained species (by some called basaltic hornblende), or 

 the same rock passing into sienitic granite, or into pegmatite.* But 

 I never saw, nor did any of the advocates of the insensible transition 

 ever observe, common granite (such as is found in the Koondahs) 

 metamorphosed into the augitic basalt which prevails there. 



* See the paragraph of Dr. Hibbert quoted at length in De la Beche's Geological 

 Manual, page 455, and also Ure's System of Geology, page 123. 



