gum (Nyssa biflora), dwarf palmetto, mulberry (Morus spp.), grape (Vitis spp.), and yaupon (Ilex vomitoria).

Above the swamp is a mixed pine and hardwood forest (Region 6).

b. Consumers

Salt water marsh consumers are waterfowl and probably marine snails, small crabs, grass shrimp, and large populations of larval marine fishes and crustaceans. Besides eating the marine grasses, the waterfowl most likely graze on the populations of small molluscs and crustaceans. Other grazing and predation only results from visits to this region by members of other communities.

The brackish and fresh water marsh offers a larger variety of food, heavier cover, and more high ground (levees on the Trinity River) than the salt water marsh and hence has a larger variety and standing stock of faunal members. In wetter areas there are aquatic animals feeding on both living vegetation and detrital material; nutria, muskrat, and waterfowl may also feed, in part, on living vegetation. Secondary, tertiary, etc. consumers can include more omnivorous waterfowl, muskrat in part, rarely mink, snakes (especially cottonmouth), predacious diving birds, and hawks and owls. In the swamp, in addition to these animals, but excluding most waterfowl, there are also raccoons, squirrels, and perching birds.

The faunal components of the mixed pine-hardwood forest community include insects, spiders, and their relatives, assorted reptiles, quail, hawks, assorted perching birds, rodents, rabbits, and coyotes.

4. The Galveston-Trinity Bay-Estuary-Lagoon System

Fisher et. al., (1972) described this system as a rela

tively low-energy (waves) environment protected on the seaward side

by well-developed barrier islands and peninsulas.

Water exchange

between the bays and Gulf is normally limited to tidal passes through the barrier islands. During storms Gulf waters also enter the bay through washovers and breaches cut through the barrier islands. Fresh water is supplied to the system by larger river systems terminating at the bay-heads, and by several small streams draining local areas of adjacent coastal uplands. Bathymetry and average surface salinity

are shown in Fig. 17.

The bay margin consists of local beaches, relict berms and bay margin deposits, and small alluvial fans and fan deltas. According to Fisher et. al., there are about 50 square miles composing a band of shoal water at the bay margin, generally less than 2 to 3 feet in depth and commonly only a few inches deep. These shoal waters support fairly extensive marine algal and grass beds. The Galveston Island grass flats are vegetated chiefly by Diplanthera, while dominant vegetation off the Trinity delta and Clear Creek, generally in waters of lower salinity, consists chiefly of Ruppia. Local areas of shoal sand flats along Galveston Island support only sparse marine grass cover. Renfro (1959) found beds of sea lettuce (Ulva lactuca) growing in winter on firm sandy or clay bottoms along the Clear Creek, Houston Point and Smith Point bay margins. He also found salt cord

grass (Spartina alterniflora) growing throughout the on- or nearshore and marshy areas of upper Galveston and Trinity Bays. Renfro considers the widgeón grass (Ruppia maritima) to be the most important component of the flora in the upper bays. It is most widespread and luxuriant during the warmer months and as winter approaches most of the plant growth is sloughed off and the grass mats diminish. The Ruppia beds serve as an important nursery, offering a sheltered environment to

many species of larval fish and crustaceans.

In this area of abundant

fresh and detrital vegetation are found amphipods, small penaeid shrimp, small crabs, worms, grass shrimp and young fish.

Other marsh and marine flora noted in the upper bays by Pullen (1960) were Lyngbya sp. a blue-green alga that was commonly found in summer months attached to mud and shell in the marsh areas; Enteromorpha sp a green alga found in spring, summer and fall on sand and mud in shallow waters; Polysiphonia sp., a red alga common in summer and attached to pilings, piers, and stalks of Spartina; and several marine grasses already mentioned in the Galveston Island transect.

Much of the bay margin of East and West Bays has been disturbed by dredging and spoil banks of the Intracoastal Waterway and is

apparently relatively barren.

Distribution of the above marine vegetation is shown in Fig. 18.

No information could be found concerning species, numbers, and distribution of phytoplankton in the bay system.