430 Lieut.-Colonel Syres on a portion of Dukhun. 



equivalent in Europe of the Indian sandstone^, as it is much associated with 

 the primitive rocks *. In fact, where are the oolitic rocks above, and the mag- 

 nesian below the red sand, where the rock salt and gypsum, and where, above 

 all, the characteristic organic remains of the has and magnesian limestone ? 

 It would be idle, therefore, to speculate on the era of a formation without a 

 standard of comparison to direct the judgement. The question of the manner 

 of the formation of the horizontal beds of trap with their vertical edges is very 

 interesting. It will be said they were ejected under the pressure of an incum- 

 bent ocean. If such had been the case, where are the marine remains, and 

 would not there have been sedimentary deposits upon them ? Moveover, if 

 viewed as coulees from craters, would not the beds have thinned out, instead 

 of preserving the parallelism of their superior and inferior planes and their 



vertical edges ? 



Laterite. 



Laterite is a ferruginous clay mottled red and yellowish. When first dug 

 from its bed, it is soft and is easily fashioned into the form of bricks or large 

 square masses for building; and if my recollection serves me right, it consti- 

 tutes the material of the walls of the fort at Tellicherry and the jail at Calicut. 

 It rapidly indurates on exposure to the atmosphere. It is destitute of fossils, 

 as far as is yet known. 



That curious and very extensive rock, aptly denominated laterite, (I learn from the information 

 of a friend,) occurs at the source of the Kristna river in latitude 17° 59', at an elevation of 4500 

 feet above the sea. It covers the low land between the sea and the great western range from the 

 southern Konkun to Cape Comorin, and, agreeably to Dr. Davy, passes into Ceylon. I casually 

 observed it at Tellicherry and Calicut, respectively 74'4 and 756 miles south of Bombay ; and at 

 Calicut granite rises through it. On the low land at the base of the great eastern range, Mr. Calder 

 says it reappears between the 11° and 12° parallels of latitude, and recurs in increasing patches 

 passing northwards, covering granite. The Rev. Mr. Everest speaks of laterite forming a fringe 

 to great part of the bay of Bengal and covering the edge of the granite of either peninsula f. 



Nodular Limestone. 



In addition to the evidence already adduced of the extensive occurrence of 

 nodular limestone. Dr. Buchanan mentions having met with it in Rajmahl 

 trap hills, in Bengal, and in Mysore. A writer in the 'Gleanings of Science';}; 

 states that it occurred in repeated borings for water in Calcutta, at from 50 to 

 112 feet below the surface. Another writer§ says, it is "very extensively distri- 

 " buted throughout Hindoostan," and further asserts that it is a ''most distin- 

 " guished feature of Indian geology." The Rev. Mr. Everest and Mr. Royle 

 remarked it in their journey before adverted to. The few organic remains 



* Gleanings of Science, vol. iii. p. 213. f Ibid., vol. iii. p. 135. 



X Ibid., vol. i. p. 169. § Ibid., vol. i. p. 365. 



