WATER-RESOURCES INVESTIGATIONS REPORT 00–4195Hydrogeologic subdivisions of the Edwards aquifer outcrop—PLATE 1
Small, T.A., and Clark, A.K., 2000, Geologic framework and hydrogeologiccharacteristics of the Edwards aquifer outcrop, Medina County, Texas
U.S. DEPARTMENT OF THE INTERIORU.S. GEOLOGICAL SURVEY
IN COOPERATION WITH THEEDWARDS AQUIFER AUTHORITY
MAP SHOWING HYDROGEOLOGIC SUBDIVISIONS OF THE EDWARDS AQUIFEROUTCROP, MEDINA COUNTY, TEXAS
ByTed A. Small and Allan K. Clark
2000
Base modified from U.S. GeologicalSurvey 1:24,000 quadranglesUniversal Transverse Mercator ProjectionZone 14
0 1 2 3 4 MILES
Seco
Creek
Hondo
Creek
Hondo
Creek
Verde
Cre
ek
Geronimo
Creek
MEDINA
RIVER
MED
INA
LAK
E
MED
INA
LAK
E
Bull
Creek
County Road
211
CountyRoad
131
FM 462
Sta
te
173
FM 1796
FM 462
FM
462
Sta
te 1
73
State
16
Park Road 37
County
Cou
nty
Roa
d
Road
251
252
FM
1283
1283FM
County
Road
271
2615
County Road
County Road 351
Cou
nty
Roa
d
265
Woodard
Cave
fault
UD
UD
Verde Creekfault
UD
UD
Woodard
Cave
fault
UD
D U
D U
UD
UD
UD
UD
UD
UD
UD
UD
D U
Seco Creek
fault
Vandenburg
School
fault
UD
UD
UD
Medina
Lake
fault
UD
Parker
Creek
fault
DU
DU
UD
Lincoln
fault
Haby
Crossing
fault
Diversion
Lake
fault
UD
UD
UD
UD
UD
UD
UD
UD
UD
UD
UD
UD
UD
UD
DU
UD
UD
UD
UD
UD
UD
DU
UD
DU
UD
UD
Rugh Sinkhole
Woodard Cave
Ney Cave
Boehme's Cave
Haby Bat Cave
Bear Springs
Sheep Springs
Cypress Springs
Indian Springs
Moccasin Springs
29o37'30"
99o22'30"
29o30'
99o07'30"99o15'
98o52'30"
99o
29o37'30"
99o22'30"
99o15' 99o07'30"
99o
98o52'30"
29o37'30"
29o30'
FACIES CHANGE
PRIMARY FAULT—U, upthrown side; D, downthrown side
U
D
U
DINFERRED FAULT—U, upthrown side; D, downthrown side�
SPRING
CAVE
Hill Country State Natural Area
TEXAS
Study area
SAN ANTONIO
UVALDE COUNTY
BANDERA COUNTY
BEXAR COUNTY
Study area San AntonioLOCATION MAP
MEDINA COUNTY
Balcones fault zone
III LEACHED AND COLLAPSED MEMBERS, UNDIVIDED
IV REGIONAL DENSE MEMBER
V GRAINSTONE MEMBER
VI KIRSCHBERG EVAPORITE MEMBER
VII DOLOMITIC MEMBER
VIII BASAL NODULAR MEMBER
UPPER MEMBER OF THE GLEN ROSELIMESTONE (LOWER CONFINING UNIT)
DE
VIL
S R
IVE
R F
OR
MAT
ION
PE
RS
ON
FO
RM
ATIO
N
ED
WA
RD
S G
RO
UP
KA
INE
R F
OR
MAT
ION
ED
WA
RD
S A
QU
IFE
R
TRINITYAQUIFER
I GEORGETOWN FORMATION
II CYCLIC AND MARINE MEMBERS, UNDIVIDED (NOT EXPOSED IN STUDY AREA)
UP
PE
R C
ON
FIN
ING
UN
IT
EXPLANATION
DEL RIO CLAY
BUDA LIMESTONE
EAGLE FORD GROUP
AUSTIN GROUP
HYDROGEOLOGIC SUBDIVISIONS I–VIII— Modified from Maclay and Small (1976)
ALLUVIUM
LEONA FORMATION
ESCONDIDO FORMATION
ANACACHO LIMESTONE
QU
ATE
RN
AR
YU
PP
ER
CR
ETA
CE
OU
SLO
WE
R C
RE
TAC
EO
US
FO
RT
TE
RR
ET
T F
M.
SE
GO
VIA
FM
.
NOTE: Segovia Formation not exposed in study area.
Koenig Creek
Geology modified on the basis ofadditional field work in Medina County.�
