560 Notices of Memoirs — Dr. W. MacMe — Fossil Water. 



doubt made manifest, the results as regards the main issue were- 

 found to be entirely negative. In all, 38 determinations were made : 

 7 in L.O.E. rocks, 17 in U.O.R., 6 in Triassic, 1 in Jurassic, and 

 for the purposes of illustration 7 in recent deposits. The averages- 

 obtained were : — 



CI, per cent. S O4, per cent. 



L.O.E -0101 ... -0180 



U.O.R -0077 ... -0064 



Triassic -0050 ... -0051 



Jurassic -0037 ... -0113 



Eeceut -0049 ... -0042 



Average over all: CI, -0063 per cent. ; S O4, "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 sulphates 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. 



Kemarkable variations were obtained in specimens from the same 

 sandstone, even when collected in the same quarry. These variations 

 were in some cases so extreme 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. It 

 has been shown elsewhere that traces of the heavy metals are 

 disseminated through the Elgin Sandstones generally, and also tend 

 to increase in relative proportion in the manganese areas. Increases 

 in lime, magnesia, and alkali have also been demonstrated as 

 obtaining in the same areas. From the intimate relationship of all 

 these substances it is inferred, with some degree of certainty, 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 result 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 circumstances. 



