Records of the Geological Survey of India. 
[vot. Viir. 
With reference to the impurity of the wells within the city walls, it is probable that 
water percolating through the accumulated debris of old mortar, ashes, burnt clay, &c., which 
have raised the surface of the ground inside the city from 10 to 20 feet, may dissolve a 
considerable quantity of various salts, and thus increase the saline ingredients of the well 
water. 
So far as I can judge, however, none of the wells in or around Surat furnish water so 
pure as ought to be obtained for drinking purposes. I am told that no complete analyses of 
these waters have ever been made, and I should recommend that such be obtained of different 
waters, including the best and the worst, since the kind of salt present and the relative 
quantities may afford some clue to their origin. 
The details just given concerning the Surat wells are certainly in favor of the conclusions 
already expressed as to the causes of irregular distribution of fresh water in the soils of 
Surat. These conclusions I will briefly recapitulate, pointing out their practical application— 
1. There appears reason to believe that the greater portion, if not the whole, of the 
alluvial deposits near the coast of Guzorat were originally impregnated with salt in conse¬ 
quence of their having been formed in salt-water. Where they are now free from saline 
impurities, this is due to the removal of such impurities by the percolation of fresh water. 
2. Such percolation of fresh water has been efficient in proportion to the elevation 
above the sea, and to the greater or less permeability of the beds ; consequently, as a rule, those 
wells which are at the greatest height above the sea and those which yield the most water 
are the sweetest. 
3. The distribution of permeable and impermeable beds is very irregular, most of the 
strata being lenticular in section and thinning out within short distances. 
4. It ensues from the above, that there is no reasonable prospect of fresh water being 
obtained from deep borings, unless the strata beneath the bottoms of the existing wells are 
generally more pervious than those near the surface. This is possible, but there appears no 
sound reason for anticipating that it will prove to be the case, and it is probable that deep 
borings will give as irregular results as surface wells. 
5. It is also improbable that fresh water will be found in wells sunk in the salt 
lands now being reclaimed. Should such be found, its occurrence will be, I think, accidental, 
and due to the existence of unusually pervious strata, and I think that these may very 
possibly prove local. 
6. The presence of fresh water in some places on the coast, as near Dumas and at 
Yaux’s tomb, appears due to, the existence of sand-hills resting on impervious clay. The 
quantity of water will probably bear some proportion to the extent of the sand-hills. 
Although a considerable supply may be derived from such places for local purposes, I do not 
think it probable that the quantity is sufficient to supply large irrigation works, nor should 
I be surprised if in some similar localities the water proved more or less brackish, owing to 
the presence of salt in the sand, or contamination from the subsoil. Deep wells amongst 
the sand-hills would probably yield brackish water 
7. None of the wells about Surat town supply really good water, nor is there at 
present sufficient prospect of improvement to justify the sinking of deep wells, and, as an 
ample source of excellent water exists in the river Tapti a few miles higher up, and I am 
informed that it is proposed to introduce the same into the city, it appears scarcely worth 
while to incur expense in experiments which are very likely to fail. 
Finally, I can only suggest that if further information be required, and to test the 
accuracy of the views here expressed, borings should be made to a depth not exceeding 
