Transect c of Fig. 13c, as shown in Fig. 20, is

typical of barrier islands and peninsulas along the central and

eastern Texas coasts.

The soil association present in this area is the Galveston-MustangRahal, a deep sandy soil of high to very high permeability, low water-holding capacity, low compressibility, low shrink-swell potential, good drainage, high shear strength, and low plasticity. (Fisher et al, 1972; and U.S. Dept. of the Army, 1973). Compared to the areas discussed above, biological productivity is somewhat lower in the area of this transect.

Region 1 is the beach, 2 is the beachridge and barrier flat, and 3, the wind-tidal flat. The beach, up to the beachridge, is sparsely populated by sea oats and a few other salt-tolerant plants. From the beachridge, through the barrier flat and up to the windtidal sand flat, the vegetation consists of moderate to dense stands of salt tolerant grasses with scattered live oak and mesquite. The wind-tidal sand flat is only a few inches above sea level and supports

a blue-green algal mat.

Region 4 is a salt marsh. According to Fisher et al. (1972) these marshes

display an orderly plant succession from the bay line to the higher Beginning at the edge of the wind-tidal flat the

wind-tidal flat.

plants are (1) sea-oxeye, seepweed, Monathocloe, (2) maritime saltwort, glass wort, salt grass, and (3) salt cordgrass.

Below the salt marsh in the shallow bay margin is a densely vegetated grass flat (region 5). Species here can include several marine grasses (Diplanthera wrightii, Ruppia maritima, Thalassia testudinum).

(b) Consumers

As in other areas, beach infauna includes

several clams and snails, and perhaps ghost crabs, along with shorebirds of various kinds. The shorebirds and ghost crabs also inhabit the drier beachridge and barrier flat, along with occasional rodents and snakes. The wind-tidal flat may have a few fiddler crabs and

occasional shorebirds.

The grass flats are populated primarily by marine aquatic species, especially molluscs. Also in the region are a few visiting shorebirds and several fish. There are probably extensive visits by heron-like predacious diving birds.

6. Coastal Zone Between Galveston and Matagorda Bay
Systems

The Pledger-Moreland soil association in this area can be clayey throughout or can have loamy surface layers underlain by clayey layers, and is saline. Local soils have moderate permeability and drainage, moderate water-holding capacity, low to moderate compressibility, and shrink-swell potential, and high shear strength (U.S. Dept. of the Army, 1973).

Insufficient information is available to allow us to discuss this

area using a representative transect as was done earlier in this section. The Texas Super Tanker Port Study (Texas A&M Univ., 1972) describes the area as undeveloped except for a few sections. Some permanent and recreation housing developments exists near the mouth of the Colorado River, the mouth of Caney Creek and from the Freeport Harbor Navigation entrance to San Luis Pass.

The beach in this region is extremely narrow, but has an almost continuous high beach ridge. Vegetation likely consists of sea oats, seacoast blue stem, and a scattering of other halophilic grasses and forbes.

The marsh varies in width from non-existent through a short stretch

beginning about 4 miles up the coast from the mouth of Caney Creek,

to about 6 miles in the Cedar Lakes-Jones Creek area.

Although no

verification was found in the literature we estimate that only a small portion of the marsh near the Cedar Lakes area, which receives regular tidal exchange, is salt marsh. The remainder is probably brackish to fresh. Marsh vegetation is probably similar to that described for regions 3 and 4 of the strandplain chenier marsh of the northeastern coast, consisting of the spartinas, bullrush, cattail, rushes, salt grass, glass wort, and numerous other forbs

and grasses.

Further inland, the marsh gives way to a prairie association known as the lower coastal range. The principal climax plants are the tall bunch grasses, typically including switchgrass (Panicum virgatum), seacoast bluestem, big bluestem (Andropogon gerardi), saltgrass, marshhay cordgrass, silver bluestem (Bothriochloa saccharoides), along with vine mesquite (Panicum obtusum), and bushy sea oxeye (Borrichia frutescens) (U.S. Dept. of the Army, 1973).

Approximately between Caney Creek and Oyster Creek, the lower coast range prairie is replaced, further inland, by an Ash-hickory-pecancottonwood forest association (Figure 13c).