530 Capt Newbold o?i a recent Fossil Freshwater Deposit in 



of the Himalayan strata, and tbe trap hills of Central and 

 Western India. 



The heat of the springs might be annually or triennially 

 noted with compared thermometers. After many experiments, 

 I find existing meteorological causes generally affect the tem- 

 perature of such springs in a sensible degree; and great care 

 should be taken, in making successive experiments, that the 

 meteorological conditions be as far as possible similar. The 

 time of the year should be the dry season, and the time of 

 day sun-set and sun-rise. 



The plains and valleys of India are often covered with 

 sheets of kunker, sometimes upwards of seventy feet deep, 

 overspreading places where it could never have been depo- 

 sited by rivers or rivulets, and where now not a spring or 

 drop of water is to be seen. Along the edges of trap dykes, 

 we occasionally observe mounds of kunker precisely resem- 

 bling those around the mouths of existing kunker -depositing 

 springs, but we look in vain for the springs that deposited the 

 former. 



Still these dwindled remains of springs are generally to be 

 found where kunker prevails at no great depth from the sur- 

 face, deprived of their heat and of the greater part of their 

 mineral character, which renders the water better adapted for 

 the use of man and animals. Most of the native diggers in 

 boring for a well, consider kunker as almost a sure sign of 

 the vicinity of water. If there can be any doubt after what 

 has been said of the certainty of the vast sheets of kunker at 

 present seen covering waterless plains, and the arid summits of 

 hills of Southern India having been formed by springs, many 

 of which are now dried up or diverted, it will be removed on an 

 inspection of a vertical section of the rocks which underlie it. 

 These, whether trap, granite, the hypogene schists, sandstone 

 or limestone, will be found invariably to be penetrated by 

 nearly vertical fissures, through which the kunker appears to 

 rise like trap in a dyke and to overflow the surrounding sur- 

 face, and like trap, to introduce itself into any horizontal or 

 other seams, imparting the appearance of beds of kunker al- 

 ternating with gneiss, &c. On a more minute inspection, it 

 will be found that the kunker has in reality been precipitated 

 chemically from the water of springs that now, or formerly, 

 found vent to the surface through these fissures. The ther- 

 mal waters holding the lime in solution as they cooled in ap- 

 proaching the surface deposited the lime as they ascended. 



I had an opportunity in 1840 of studying the formation of 

 travertine in the old volcanic area around Rome, and found 

 it to assimilate that of the Indian kunker in all the leading 



