1840.] 



Geological Desiderata, 



247 



is often concealed from view by the masses of rock it has uplifted. It 

 is in ihe deep transverse valleys and <difts through ranges, and in low- 

 situations near their termination, in wella and other artificial or natural 

 sections, that we are most likely to discover the true direction of the 

 main dyke. To the soulevemeni of sotne of these branches may be at« 

 tribufed those low ranges of hills, called spars, that often diverge at 

 right angles from the direction of the principal chain. 



5. — The calcareous deposits 1 have alluded to in No. 4, may be 

 divided into two classes — ancient and modern. The latter, is still sup« 

 posed to be in process of formation. Observations tending to the 

 various rates of progressive accurauU^tion of the latter, and the rationale 

 of its deposition under various conditions, would be instmctive. 



6. — Chemical analysis of the water in the springs and rivers of India 

 during the dry and rainy seasons. Fiom a careful examination of the 

 latter an approximative idea might be obtained of the nature and quan^ 

 tity of calcareous and other matter, annually added from the land to the 

 waters and bed of the ocean. 



7. ~There are large plateaus of sandstone on the summits of some of 

 the ranges in the Ceded Districts, covered with ripple marks, — the 

 general direction of which, and the slope of the country, show that the 

 current of water that flowed over these beds anterior to their consohda^ 

 tion, must have hrid a south-easterly direction. I cannot call to mind 

 that ripple marks have yet been noticed on the sandstone formations of 

 India : but it is highly probable they do exist ; and it would be desira- 

 ble to search for them and note their direction, bearing in mind that 

 the course of the great diluvial stream that flowed over these sands 

 and clays, would be at right angles to the general direction of the rip- 

 ple lines. 



8. — Frona certain appearances near Nellore, Madras, Mavellipurara, 

 and the present mouth of the Cauvery, it is certain that the sea in 

 these particular localities on the Coromandel coast has advanced on 

 and submerged considerable tracts of land ; and two cities, according 

 to tradition (at Mavellipuram and the ancient embouchure of the Cau- 

 very), are now covered by the waves. The sea appears to be receding, 

 or, more correctly spenking, the land appears to be rising in these par- 

 ticular localises. It is probable that, as on the Swedish coast, certain 

 parts of the Coromandel coast, instead of participating in the progres- 

 sive elevation of the land, sutter a lowering of level; while other por- 

 tions remain stationary. I have observed similar indications of the 

 sea having covered various parts of the Malabar, or western coast, 

 to a considerable distance inland, in the existence of a former bed 



