104 CRETACEOUS ROCKS OF S. INDIA. [PaRT II. § 1. 



where the formation is at its greatest width, a current coming from the 

 North-west, or from the direction of Perambaloor t3rought down a larger 

 supply of sediment than accumulated elsewhere. Now this direction is 

 that of the North flank of the Patchamullies, a hill group, which, as 

 I shall presently show, must have existed previously to the commence- 

 ment of the Cretaceous period, and the general outline of which we 

 may well believe to have been about coincident with that of the Creta- 

 ceous shore line, and thus the greater accumulation of sediment, in the 

 area I have indicated, is the natural result of the existence of a long 

 shore current from the Northward, which here leaving the land (indicat- 

 ed by the outline of the hills) deposited the suspended and drifted sedi- 

 ment in the deeper waters of the sea beyond in the form of a great 

 bank. Upon this hypothesis we see why we should have a great accu- 

 mulation of sub-littoral forms of MoUusca, &c., in the Northern half of the 

 area, while they are almost absent to the South, where comparatively 

 still water prevailed, as indicated by the fine sediments composing that 

 part of the group.* We see also how, as the bank advanced further and 

 further seaward, the sea above it becoming gradually shallower by its 

 formation, coarser materials should be constantly swept further outwards 

 and o-radually gain on the area of the finer sediments as we have seen 



* The physical geography of the coast of Tanjore and Northern Ceylon exhibits a state of 

 things in some respects analogous to that which I suppose to have obtained in the Trichinopoly 

 area during the Ootatoor period. A great current with a velocity during certain periods of the 

 year, of 4 or 5 miles an hour, sweeps up or down the coast, the du-ection changing with that of 

 the monsoon, and the deposits along this shore line are sands with numerous di'ifted shells of 

 Bub-littoral species which are washed up in great quantities on the sti-and. Meanwhile 

 the bay to the South of Point Calimere is, at all times, comparatively stUl water, and, 

 as I am informed by Mr. CadeU, a great bank of the finest mud is here formed and 

 is gradually silting up the bay. During stress of weather ships lying off Negapatam 

 and neighbouring roadsteads frequently run into this bay and are thus quite sheltered. 

 Now if this current were perennially from the North, Ceylon non-existent or at twice 

 its present distance, (for the mountains of Ceylon formed in all probability an island 

 of the Cretaceous epoch,) and Point Calimere, a rocky headland instead of an alluvial 

 sandy flat, we should have the hypothetical geography of the Ootatoor period exactly 

 reproduced. 



