Subject
Geology
290
Texas History
149
Water quality
142
Groundwater
127
Geology, Stratigraphic
119
Texas Description and travel
107
Texas
92
Water-supply
84
Frontier and pioneer life
75
Paleontology
66
Hydrogeology
60
Edwards Aquifer (Tex.)
53
Aquifers
50
Post office buildings
46
Stream measurements
44
Water Pollution
41
Streamflow
39
Petroleum
32
Hydrology
31
Mines and mineral resources
30
Public buildings
29
Groundwater flow
28
Floods
26
Natural gas
26
Indians of North America
24
National parks and reserves
24
Petrology
23
Courthouses
22
Texas Politics and government
22
Oil fields
21
Groundwater Quality
19
Land titles Registration and transfer
19
Uranium ores
19
Auditing
18
Texas Annexation to the United States
18
Groundwater Pollution
17
Rules and practice
17
Texas Emigration and immigration
17
Environmental impact statements
16
Historic sites Law and legislation
16
Land grants
15
Petroleum Geology
15
Big Bend National Park (Tex.)
14
Cattle trade
14
Environmental impact analysis
14
Texas Altitudes
14
Water resources development
14
Geology, Economic
13
History
13
National parks and reserves Law and legislation
13
more ...