Haworru. | Physical Properties of the Tertiary. 273 
rolled down the side of the hill so rapidly that vegetation can not 
grow on it, showing that it is very recent in its movements. Yet the 
light layers of sand, inclined at as high an angle as it is possible for 
them to lodge on the hillside, are cemented sufficiently to cause the 
wind erosion to develop stratification marks within them. An 
example of this at one place seems to show that some of these sand 
layers had been moved during the last six months, and that the 
cementing material had been deposited by water working its way 
down the hillside after the little rains of the summer. 
It is not an unfrequent occurrence to find slight incrustations on 
the surface of the sand in the beds of different creeks over which 
the water carrying acid calcium carbonate has probably passed 
producing a rearrangement of the sand beds less than three months 
previously. More than a dozen such instances were particularly 
noted and carefully examined. 
The conclusions arrived at regarding the deposition of calcium 
carbonate are in harmony with well known facts regarding the 
accumulation of alkaline materials and other soluble salts over arid 
areas which have imperfect sub-drainage. It is well known that all 
such localities abound in soluble salts that have been produced by 
the decay of surface material and segregated by running water 
which was subsequently dried up. The famous illustrations of the 
world are the shores of the great inland seas, such as the Caspian 
sea, the Dead sea, and the Great Salt Lake, with a larger number 
of less noted instances occurring throughout the arid country, such 
as the broad sand-covered valleys of almost all the mountainous 
streams which flow downward through the parks and valleys where 
precipitation is light. Water obtained from such places is prover- 
bially mineralized until it is unfit for domestic uses, the mineral ma- 
terial being accumulated in this well known manner. 
THE CLAY BEDS. 
In some respects the position and character of the clay beds are 
of importance. As the clay deposits were formed from water with 
almost no current they represent the opposite extreme from the 
gravel deposits, and are therefore equally important in a study of 
Sls 
