20 University of Kansas Geological Survey. 
they contain water intermittantly. It has now been five years or 
more since any of them have held water for any continuous time. 
During July and August of 1895 they were nearly filled from the 
north side of the state to the south. But the water soon sank away, 
or was evaporated, so that they were entirely dry for perhaps 
eleven months out of the year. 
In some parts of the state there seems to be no relation between 
these swales of various size and shape and the drainage channels. In 
other places there is an undoubted relation. Frequently an arroyo 
has been found heading toward a row of such swales. When we 
come to ask the question regarding the source of the swales we find 
it hard to answer. Different views have been expressed by different 
intividuals. The one which the writer deems most probable is 
that they are located in places where the Tertiary materials were 
not quite as solid and firm as elsewhere, consequently, by the 
natural settling process, a difference in the surface was produced. 
As soon as such a depression was formed the rain waters from the 
higher grounds around would drain into it, and consequently a 
greater novement of water immediately under it would take place. 
This accumulation of water would dissolve and carry away by down- 
ward percolation a greater amount of matter than would be dis- 
solved elsewhere. It is reasonable to suppose that in the deposition 
of the Tertiary sands and clays a somewhat heterogeneous character 
would be produced and that here and there would be streaks where 
the material would not be quite so firm as the average, and would 
consequently settle more irregularly. In this way would be formed 
a stving of little swales which would become deeper and more pro- 
nounced as the solvent action was continued. An arroyo is only 
one step further. The continuous dissolving of the material under 
the swales would draw them nearer together and ultimately the 
barriers between them would be broken down and the arroya would 
result. 
Such a relation between the swales and arroyos is frequently 
noticeable in southwestern Meade county, perhaps more so than 
anywhere else in the state. It is frequently noticed that immedi- 
ately above one of the upper branches of an arroyo a chain of 
swales is found reaching backward for a distance varying from a 
