56 The American Geologist. January 1902. 
which is basined similarly to the surface, thus depressing the surface of 
the ground water; (3) An outlet, draining the basin; otherwise it would 
fill and form a lake, for all these clay strata are only relatively im- 
pervious, that is, they can only retard the water’s rise to its surround- 
ing level. These conditions are fulfilled in the Meade basin, which 
was studied in detail, and to some extent in a few others. Few of the 
many basins have their bottoms below the level of ground water which 
is, in general, probably little short of one hundred feet below the sur- 
face. “The fact that under normal conditions, the water plane in 
desert lowland regions of seaward inclination nowhere intersects the 
surface, but on the contrary, is almost universally lowlying is not to 
be attributed to the relatively light precipitation. The explanaton is 
to be looked for in the deep burial of the bed rock under open-tex- 
tured material, which affords opportunity for relatively large drain- 
age.” 
The impression is not to be left that the high plains can not be 
reclaimed. It is the author’s declared purpose to show “that on the 
other hand, water from under ground is obtainable in sufficient amount 
for reclamation of the entire area to other uses; that such reclamation 
has in fact already begun, and is in progress of gradual but sure de- 
velopment; and that it will be universally profitable.’ Among the as- 
sured advantages toward this reclamation are (1) everything necessary 
for phenomenal success in the raising of cattle, (2) reasonable certain- 
ty of drought-resisting crops, such as sorghum which may be used 
as forage, (3) a supply of water from wells, sufficient for domestic 
purposes and stock and sometimes for gardens; likewise the wind 
with which to pump it. These points of advantage are not specifi- 
cally mentioned in the paper, which is to be completed in a supple- 
mental publication. N. M. F. 
A preliminary report on the roads and road-building material of Geor- 
gia. By S. W. McCatttr, assistant geologist. (Geol. Survey of 
Ga., Bull. No. 8, 264 pages, 1901.) 
A fair idea of the scope of this report may be had from the chapter 
headings, which are as follows: (1) History of road construction, 
(2) The value of good roads, (3) Road construction, (4) Maintenance 
and repair of roads, (5) Road material, (6) Tools and machines used 
in highway construction, (7) The topography of Georgia in its rela- 
tion to the highways, (8) The road-building material of Georgia, 
(9) The roads of Georgia, with a brief description of the equipment, 
methods of road working and materials, by counties. The last chapter 
occupies more than half the book. Some facts of geological interest 
are given in the fifth, seventh and eighth chapters. In the latter the 
state is divided (from northwest to southeast) into a Paleozoic, a 
Crystalline and a Tertiary area, and the rocks of importance for road- 
building in each area are described. The diabases seem to be regard- 
ed as the rocks of most value for road materials, and dikes of these are 
not uncommon in the Crystalline area. These dikes are most probably 
of Jura-Triassic age, but, according to the map showing their distri- 
