4 GENERAL OBSERVATIONS ON THE 



northern Concan, to a considerable distance eastward above and beyond 

 the Ghats, as far perhaps as the river Tmnhoodra and Nagpore. These 

 rocks assume all the various forms of basaltic trap, passing from the 

 prismatic and columnar (of which some fine specimens are to be seen 

 opposite to Bassiii, near Bombay) into the globular, tabular, porpliy- 

 ritic, and amygdaloidal ; the two latter containing an interesting varie- 

 ty of included minerals peculiar to such rocks. The landscape here 

 exhibits all the characteristic features of basaltic countries. The hills 

 rising abruptly in perpendicular masses of a tabular form, or in mural 

 terraces, piled on each other, like great flights of steps leading to some 

 giant's throne, are frequently separated by immense ravines — the whole 

 clothed with luxuriant forests of teak and other trees, producing some of 

 the most beautiful and romantic scenery of India. The elevation of this 

 part of the range seldom exceeds 3000 feet ; but advancing to the south, 

 its height gradually increases, and granitic rocks begin to re-appear, rising 

 above the surface between 17' and 18° N. Latitude, and from thence, proba- 

 bly, continuing to form the summits of the chain, with little interruption, 

 all the way to Cape Comorin. In nearly the same parallel of latitude, this 

 trap formation is observed to terminate also on the sea-coast, a little to 

 ,the north of Fort Victoria, or Banleot, where it is succeeded by the iron- 

 clay or laterite,* (a contemporaneous rock associating with trap) which 



from 



* We owe the first notice of this interesting Rock, which may, perhaps, be considered as pe- 

 culiar to the Geology of this country, to Dr. Francis Buchanan, who gives the following description 

 of it in his travels, vol. 3, p. 440. " What I have called indurated clay, is not the mineral so called 

 " by Mr. Kirwan, who has not described this of which I am now writing. It seems to be the Argilla 

 « Lapidea of Wallerius I. 395, and is one of the most valuable materials for building. It is diffused 

 " in immense masses, without any appearance of stratification, and is placed over the granite that 

 " forms the basis of Malayala. It is full of cavities and pores, and contains a very large quantity of 

 " iron, in the form of red and yellow ochres. In the mass, while excluded from the air, it is so soft, 

 «' that any iron instrument readily cuts it, and is dug up in square masses with a pick-a?^, and imme- 

 " diately cut into the shape wanted, with a trowel, or large knife. It very soon after becomes as hard 

 " as brick, and resists the air and water much better than any bricks that I have seen in India. I 



