Chap. I.] general sketch of area. 21 



In the Blue Book published by order of the House of Commons in 

 consequence of the ajipointment of a Committee to enquire into the 

 working of the original Porto Novo Iron Company, in all the numerous 

 letters by Mr. Heath, the founder of that Company, and others on the 

 subject of the monopoly of the iron ores in Salem and other districts, 

 nothing is said as to the mode in Avhich the magnetic iron occurs, nor 

 are any of the localities indicated where such ore is to be met with. 

 Similarly, although frequently alluded to in these letters and also in the 

 leases granted by the East India Company to the Porto Novo Company 

 of the monopoly of Avorking the chromate of iron, as well as the mag- 

 netic iron, the locality or localities at which the chromic ores occur are 

 no where named. 



In the Geological Map of India compiled by the late George B. 

 Greenough, the geological and physical structure of the country are 

 very far from correctly laid down. The chief error which he fell into 

 regarding the country now to be treated of, consists in ascribing to the 

 several mountain ranges (which are not correctly laid down as to shape 

 and position) nuclei of granitic rocks extending over the entire plateaux. 

 The position of the cretaceous rocks is also too much to the westward, 

 and encroaching on the metamorphic low country, and the post-cretaceous 

 rocks have all been colored as alluvium only. 



An important contribution to the knowledge of the geology of 

 the Trichinopoly and Madras districts was supplied by the Rev- 

 erend C. F. Muzzy, of the American Mission in Madura, to whom a 

 copy of Greenough's Geological Map of India had been referred for 

 report. In his reply to Government on that subject, (published in 1857,) 

 after correcting numerous errors in the map, he proceeds to point out 

 some of the more remarkable features of the country lying between the 

 Collectorates of Tinnivelly on the south, and the Collectorates of Salem 

 and South Arcot on the north. With regard to soils, he mentions that 

 they usually agree with the subjacent rocks, excepting in the case of 



(21.3) 



