Chap. Xlt.] soils and superficial deposits. 183" 



3. Regur. — The soil known as regur or cotton-soil covei's a large 



^ • 1 I „ area in Trichinopoly and South Arcot. Its most 



Common mmeral cha- ^ J 



facter of regur. characteristic form is a black or bluish black 



tenacious mud, which, after prolonged heavy rain, is almost impassable 



even to a pedestrian, while, after a long continuance of dry weather, it 



is seamed in every direction with gaping cracks whicli frequently 



extend to a depth of many feet. In some parts of India this soil is 



remarkable for its fertility, but such is by no 

 Fertility. ... 



means the case in Trichinopoly. Until the 



recent reduction of the land tax, the greater part of it was left uncul- 

 tivated, and on its huramocky rough surface, little else grew than tufts of 

 dry wiry grass and a few low shrubs, such as Jatropha glandulifera* 

 Acacia auricidata, Ninum oleander^ with Sanseviero Zeylanica, and 

 A rgemone Mexicana. When cultivated, cotton, and occasionally castor- 

 oil, and some of the poorer grains, such as varaghoo, are its chief 

 products. 



Other forms of regur that I have met with are a stiff black clay. 

 Exceptional forms of which is, however, not very commom, and occurs 

 ^^"^* interbedded with the more common variety of 



the soil and clay or mud of a pale grey or yellow color, the latter 

 on the Cretaceous rocks only, and evidently owing its color to an 

 admixture of the Cretaceous clays beneath. 



No fossils have been met with in the actual regur, but a de- 

 posit of estuarine shells, into which the regur passes near Porto 

 Novo, will be noticed further on ; kuukur is common, and when 

 it occurs on the Cretaceous rocks, is probably in part derived 

 therefrom : it appears, however, generally to be of original formation 

 in the regur. 



* For the identification of these and other plants mentioned in these pages I am indebt- 

 ed to my friend Dr. T. Thomson. 



