12 
stratified, and had been precipitated in sheets as a sediment, 
and not formed by any local change of carbonate of lime. 
The salt wells of Salina are sunk not in the rocks of the Salina 
group, but in the gravel and sand which fills a trench cut 
more than 400 feet deep along the outcrop of the formation. 
This trench, or buried channel, was evidently an ancient 
water-course, and one of an extensive series of buried river- 
channels that were formed when the continent stood much 
higher above the ocean, than it does now. The salt water 
which saturates the drift that fills the old river-bed at Salina, 
flows out of the Salina group; and since it is nearly a sat- 
urated solution, it must be formed by the dissolving away 
of masses of salt which liesomewhere in the formation, either 
as beds of rock-salt or as disseminated crystals, in all proba- 
bility the former, and though these have not yet been dis- 
covered, we may nevertheless feel almost certain of their 
existence, as the source of the brines. 
He also alluded to Dr. Goessman’s theory of the deposition 
of salts, by which an explanation may be given of the re- 
markable local differences in the brines, as a result of the 
different solubility of various contained salts. In the evap- 
oration of a body of water of this kind, there will be a series 
of precipitations: first, the less soluble gypsum; second, the 
salt; third, the calcic and magnesic chlorides (‘‘ bitters”). 
It thus becomes possible to trace the deeper and shallower 
parts of such an ancient sea or lagoon. In a series of con- 
nected basins, produced by irregularities of the bottom, those 
that lay highest would contain only or mainly gypsum; those 
next below, gypsum mingled with salt, etc, while the last 
and lowest basins would have an excess of the “ bitters,” 
retained as long as possible in the evaporating water. We 
have a marked instance of such local differences in the salt 
wells at Goderich, Ontario, which also belong to this forma- 
tion. The salt here is in some cases so pure as to contain 
98 per cent. of sodic chloride, with scarcely any admixture of 
“bitters,” while in the immediate vicinity are other wells in 
which these latter salts are found in excess. 
