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



even into the Ai-rialoor group. It may, indeed, be a question whether the bed at Pondi- 



cherry in which these fossils occur be the precise stratigraphical representative of the bed at 



Ninnyoor, or whether, (the Arrialoor beds having greatly thinned out towards the North,) 



it may not represent a portion of the lower zone, in which the more recent forms above 



enumerated appeared locally at an earlier epoch than in Trichinopoly. Again, it is possible 



that in the thickness of a few feet, we may have in South Arcot the representatives of a great 



part of the Arrialoor formation of Trichinopoly, and thus the association of the fossils in 



question be rather apparent than real. Some circumstances, which will appear in the sequel, 



seem to confinn this as the most probable view. 



Meantime, to return to local details. The Ninnyoor calcareous beds are met with again 



about a mile further to the North, in the nullah to the East 

 Beds at Yellaukdumboor. ,. , .,, r. r i i mi . -i 



of the vulage of Yellakudumboor. They are here veiy sunuar 



in mineral character to those above described, biit are poor in fossils, and I only met with 



one or two ill preserved specimens of JV. Danicus, and the large Crassatella -. beyond 



this, nothing is seen of any fossiliferous beds for a considerable distance, and it is probable 



that the beds in question disappear beneath the alluvium. Beds 

 Higher beds at Thoolaur. „..,.,, , , . , . , 



of similar mineral character occur, however, higher up m the 



series, and are seen near the village of Thoolaur, 4 miles North-east of Ninnyoor, thence 



they strike to the East of Thombarapoondy, and may be traced by theu' debris on the sui-foce 



from a point a little to the North of the latter place, to the bank of the Cautoday nullah, 



opposite Mooticoorchy, where they are laid bare in the bed of 

 Fossil bed at Mooticoorchy. , -»-r . ., ■. i •■ ■ , ■, . . 



the nullah. No lo.^sils are observable in them up to this point, 

 but here the bed is full of specimens of Nautilus Danicus, most of them of gigantic size. 

 The bed is only exposed in the nullah and in the bank above, and beyond it is concealed 

 by alluvium. Finally it re-appears in the bed of the Vellaur about a mile to the North of 

 Aulathor, forming a broad stony barrier across the river, 

 where the water is low : the bank above is fonned by a little 

 cliff of Cuddalore sandstones. At this spot a few fossils occur ; among them, N. Danicus, 

 some Turritella, a Ro.itellaria, and a few bivalves. 

 Between this band and that of Ninnyoor, the Cretaceous rocks, so far as they can be seen, 

 appear to consist of sandy clays and soft shales, with a band of 

 flints exactly resembling in the mineral character, and the nature 

 of the enclosed organisms, the chalk flints of Europe. I did not see this in place ,but to the 

 west of Coorchycolum the flints appear at the surface, and are collected by the natives for 

 the same piu-pose as similar flints were in Europe previous to the invention of lucifer matches. 

 They are much shattered, and appear to form a continuous band rather than isolated nodules- 

 They are full of foraminifera, and occasionally contain small corals and other fossils of large 

 size. At only one other place did I meet with similar flints, viz., about a mile to the South- 

 east of Sainthoray, (6 miles South of Coorchycoliun,) and they were there of precisely the 

 same character as at Coorchycolum. It is possible that the band is continuous between the 

 two places, although not even ; for the whole of this country is so covered with red soil, that 

 only at veiy rare intervals is the underlying rock rendered visible. 



With this I conclude the description of the Arrialoor beds of Trichi 



nopoly ; the formation, as already mentioned, re-appears in South Arcot 



