io8 The American Geologist. February, 1904. 
under the evaporation process. The Stassfurt deposits are some 
1200 feet in depth and the lowest beds holds 625 feet of pure 
salt. At Sperenberg, near Berlin, the deposits are said to have 
been pierced 4200 feet without reaching their base. At Wielcza 
the salt deposit is 4600 feet thick. A mass of salt is described at 
Parajd, Transylvanit, with length 7550 feet, breadth 5576 feet 
and depth 590 feet. When we consider that 93 per cent, of the 
volume of sea water must be evaporated in order to throw 
down the salt it is difficult to imagine the physical conditions 
of either sea or lake which could precipitate such localized 
masses in such pure state. The remarkably deep and pure de- 
posits at Petite Anse in the Mississippi delta are still unex- 
plained. 
Salt masses sometimes contain inclusions of hydrocarbons, 
hydrogen, carbon dioxide and nitrogen, which strongly sug- 
gests the association found in volcanic emanations. 
The aridity of climate necessary for the production of salt 
deposits by evaporation must be taken into account ; and salt 
masses are found in strata as far back as the Cambrian. This 
fact seems positively inconsistent with the factors of climate 
required by the old hypothesis, as will be noted later. 
It may be possible wholly to explain the salt deposits under 
the evaporation theory, but if so it is time it were done. The 
delay and difficulty suggest the wisdom of trying a nev.- line 
of attack. 
GEOLOGIC CLIMATES. 
While climatology is immediately a province of meteor- 
ology, under the new hypothesis, which we are favoring, not 
only the origin of the atmosphere, but its subsequent changes 
in composition, producing climatal variations, are due to geo- 
logic processes. The new geology involves a new meteor- 
ology. Instead of the highly carbonated atmosphere and trop- 
ical climate of early geologic time, according to the old hy- 
pothesis, with slow decarbonation and cooling, culminating in 
the refrigeration of the present day and pointing to a "final 
winter," we shall regard the past climatic conditions as not 
radically unlike those of the present. We shall recognize that 
throughout geologic time there have been such variations in 
climate, periods of cold and aridity or of heat and moisture, as 
we know have occurred since the middle Tertiary. The pale- 
