HORTON — GEOLOGY OF THE STONESFIELD SLATE. 



249 



Let us in conclusion examine tlie nature of tlie waters wliich now 

 impregnate the great mass of lower palaeozoic strata in Canada. 

 According to Mr. Hunt in tliem " only about one-half the chlorine is 

 combined with the sodium (common salt), the remainder exists as 

 chlorides of calcium and magnesium, the former predominating, while 

 the sulphates are present only in small amounts." 



Comparing the composition of these waters, which may be regarded 

 as representing that of the ancient palaeozoic sea, with our modern 

 ocean, we find, as we have already theoretically inferred, that the 

 chloride of calcium (lime) has been replaced by common salt (chlo- 

 ride of sodium), a process involving the presence of carbonate of soda 

 and the formation of carbonate of lime. 



Let us now finally return to our question. Was the sea always 

 salt ? If what we have deduced be correct, we may answer that the 

 first ocean was one highly charged with various salts, chiefly chlo- 

 rides of calcium and magnesia ; that, with the continued action of 

 atmospheric waters bringing do^vn carbonate of soda to the sea, a 

 chemical process has been constantly carried on, by which the 

 chlorides of calcium and magnesia have been gradually but con- 

 tinuously diminished, and the quantity of chloride of sodium, or 

 common salt, proportionately increased, and consequently that the 

 saltness of the sea is gTeater now than in its ancient state, and has 

 been constantly increasing from the remotest times unto our own. 



ON THE GEOLOGY OE THE STONESFIELD SLATE AND 

 ITS ASSOCIATE FORMATIONS. 



BY WILLIAM S. HORTON, OP LIVERPOOL. 



Theee are, perhaps, few spots richer in the " time-hallowed memo- 

 ries of the past" than the old town of Woodstock, near Oxford. In 

 its immediate neighbourhood once stood a royal palace, where, as the 

 readers of Scott will doubtless remember, many of the scenes in one 

 of his novels are laid. The site of this ancient fabric is now occu- 

 pied by the more stately pile of Blenheim, the princely residence of 

 the Duke of Marlborough. In the park there is a spring still termed, 

 in allusion to the legend more or less familiar to all students of Eng- 



VOL. ID. 2 I 



