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Transactions Texas Academy of Science. 
tion more faithfully than that made by this line. Going westward, 
successive changes unfold themselves in panorama somewhat as 
follows : 
Miles west of 
the Sabine. 
Elevation in 
feet. 
Approximate 
annual rain- 
fall in inehes 
Physiography 
and Soils. 
Character of the 
Vegetation. 
Orange on 
the Sabine.. 
0 
12 
ca. 50 
Flat Coast Plain; 
low sandy ridges ; 
river bottom; 
bayous. 
Coast prairie with wet-soil 
grasses, e’ c.; cane and reed 
swamps ; dense cypress and 
tupelo swamp forest ; heavy 
pine forest ; mixed forest of 
“Big Thicket” type. 
Houston 
106 
40 
ca. 45 
Flat Coast Plain; 
higher sandy 
knolls and ridges 
cut into by drain- 
age channels, e. g. 
Buffalo Bayou. 
Western border of Atlantic 
type of continuous forest; 
western limit of southern 
pine; coast prairie with 
wet-soil grasses, rushes, 
sedges and many prairie 
annuals ; prairie marshes 
with spider lily, Sesban, etc. 
Luling 
260 
416 
ca. 33 
Rolling country, 
sandy loams, 
gravelly clay 
ridges, rich, allu- 
vial bottom land. 
Grass land with many 
prairie annuals— compos- 
ites, labiates, mallows; 
open savanna-like occur- 
rence of live and post oak 
and heavier post oak tim- 
ber; numerous sand and 
gravelly soil species, in- 
cluding several cacti. 
San Antonio.. 
316 
686 
ca. 29 
Inner border of the 
Rio Grande Plain, 
slightly rolling; 
deep porous soils; 
southern margin 
of Plains Region; 
roughly eroded 
escarpment of 
Edwards Plateau ; 
limestone. 
On Rio Grande Plain, So- 
noran species — mesquite. 
huisache, Opuntia sp.,Zizy- 
phus, Acacia sp., brasil; 
dry soil grasses and annu- 
als. On limestone hills, 
characteristic hill timber — 
cedar, mountain live oak, 
shin-oak, cedar-elm, etc. 
S p of ford 
(Ft. Clark).. 
449 
1015 
ca. 24 
Northern border of 
Rio Grande plain; 
rolling; ridges 
covered with 
gravel, flats with 
finer soils. 
Typical chaparral, more 
open formation, average 
height of woody growth 
much reduced; much Leu- 
cop h y 1 1 u m, Parkinsonia 
texana and Microrhamnus ; 
mesquite and Acacias as 
eastward. 
Del Rio 
486 
956 
ca. 20 
Alluvial valley o f 
Rio Grande River ; 
rough margin off 
Edward’s Plateau; 
ridges with coarser 
limestone frag- 
ments, flats with 
calcareous clay 
and alluvial soils. 
Chaparral, two to three feet 
tall in more open forma- 
tion; huajillo, Leucophyl- 
lum, Parkinsonia texana; 
more cacti; grass cover 
broken, scattered bunches. 
