608 REPORT— 1902. 



As a general summary it may be stated that the principles involved in 

 Weldon's process for the recovery of manganese were long anticipated and had 

 long been in operation in Nature's processes before Weldon's day. 



11. Tlie so-called ^ Fossil' Water of Sedimentary Strata, as illustrated by 

 the Sandstones of the Moray Firth Basin. By William Mackie, M.A., 

 M.D. 



A series of determinations of the soluble chlorides and sulphates locked up in 

 the interstices of the Elgin sandstones ■was made to test the thesis that from such 

 an examination it is possible to determine the character, as to freshness or salinity, 

 of the -waters of the basin of deposit of a series of sedimentary rocks. 



In the present case, though some interesting side issues -were no doubt made 

 manifest, the results as regards the main issue -were found to be entirely negative. 

 In all, thirty-eight determinations were made : seven in L.O.R. rocks, seventeen 

 in U.O.R., six in Triassic, one in Jurassic, and for the purposes of illustration seven 

 in recent deposits. The averages obtained were : — 



CI per cent, SO j per cent, 



L.O.R 'OlOl -0180 



U.O.R. 

 Triassic 

 Jurassic 

 Recent 



Average over all — C'l, -0063 per cent. ; SO4, -009 per cent. 



Some interest attaches to these averages in relation to the question of the 

 saltness of the sea. They show at least that a fairly large proportion of that 

 saltness may reasonably be referred to the washing-out in past times of the chlorides 

 and sulphat(;s from sedimentary rocks. 



The increase shown by these averages from the younger to the older formations 

 — or, to put it otherwise, from the overlying to the underlying rocks — may be 

 ascribed to the washing-in of the soluble salts from the surface and concentration 

 in the depths ; but doubt may be expressed if that covers the whole case. 



Remarkable variations were obtained in specimens of the same sandstone even 

 when collected in the same quarry. These variations were in some cases so ex- 

 treme as to preclude any general conclusion as to the character of the waters of 

 the basin of deposit. It was also found that the percolation of rain-water may 

 reduce the chlorides to '0005 per cent, or less, and the sulphates to a like quantity, 

 or even to entire absence. Water passing down joints and fissures, it was also 

 found, tends to wash back the soluble salts and concentrate them at some distance 

 back from the fissures. Chlorides, and less frequently the sulphates, were found 

 to increase in rocks secondarily stained with ferric hydroxide, and also in the 

 manganese areas referred to in the author's paper. It has been shown else- 

 where that traces of the heavy metals are disseminated through the Elgin sand- 

 stones generally, and also tend to increase in relative proportion in the manganese 

 areas. Increases in line, magnesia, and alkali have also been demonstrated as 

 obtaining in the same areas. From the intimate relationship of all these sub- 

 stances it is inferred, with some degree of certaint}', that they formed part of the 

 same general infiltration. If so, it must also be inferred at the same time that the 

 original ' fossil ' water of these sandstones must have long ago been washed out, or 

 at least seriously masked in the process. Generally it may be said that such 

 washing-out of the original ' fossil ' water may have taken place anywhere, and 

 that the results of subsequent infiltrations may have themselves been replaced again 

 and again by other infiltrations, and so on. The inference therefore, that the 

 soluble salts of a series of deposits represent the salts of the original waters of the 

 basin of deposit must in the majority of instances be a very uncertain one, if indeed 

 any degree of certainty can be claimed for such an inference under any circum- 

 stances. 



