Stone Implements in Lateritie formations. 23 



as figured in the Geologist Magazine for 1861, page 25, and 

 is but very little more rude than the analogous obsidian 

 flakes used by the Aztees as razors at the time of the Span- 

 ish Conquest of Mexico and up to a later period. 



The total absence of organic remains from the formations 

 containing these specimens of human workmanship renders 

 it very difficult to arrive at any satisfactory conclusion as 

 to the circumstances existing during their deposition over 

 so wide spread an area. 



There seems reason to believe, however, that the lateritie 

 conglomerates and sands were deposited at the bottom of a 

 shallow sea studded with mountainous islands between 

 which flowed strong and rapid currents. This sea flowed 

 far up among the quartzite mountains of Naggery and 

 Calastry. The few islands which raised their heads above 

 its surface, were probably only those points exceeding 400 

 feet in elevation above the present sea level, including in the 

 immediate neighbourhood of what we now know as the city 

 of Madras, the Palaveram, Yendaloor and Mullapode hills. 



Further South only the Apoor Hill, and the summits of 

 several hills at Condingee, Chingleput and Tirukarikunum 

 formed a sporadic Archipelago. 



In a westerly direction the laterite sea probably broke 

 against a generally low gneiss coast trending in a N. 

 N. E. direction, from near Covrepauk to the neighbour- 

 hood of Naggery Nose. East and N. E. of the Naggery Nose 

 mountain, three or more rather large islands lay off the 

 coast and in a great measure yielded the materials of which 

 the lateritie deposits are formed. These islands which now 

 form the Alicoor and Sattavadu hills were very probably 

 inhabited or visited by the people who made the quartzite 

 Implements which are at present the only record of their 

 existence. 



