Skip to Main Content
Skip Nav Destination


1. Foraminifera populations have been analyzed from approximately 320 equal-size samples of surface sediment from a nearshore area on the southwest coast of Texas.

2. The Foraminifera populations are grouped into four biofacies, as follows: open gulf, bay, marsh, and river biofacies. Two subfacies are distinguished a beach subfacies and an upper San Antonio Bay “subfacies.” Mixed faunas occur in the lower bays, particularly near passes.

3. Two principal factors causing the biofacies distribution in this area are believed to be the presence of barrier islands with narrow passes and variations in runoff into the bays. During times of low runoff oceanic water invades the bays, evaporates, and relatively high salinities result. Many of the open gulf species invade with the oceanic water masses al times of low runoff, and appear to become established within the bays. These species may be killed off during prolonged high runoff and consequent decrease in salinity.

You do not currently have access to this chapter.

Figures & Tables





Citing Books via

Close Modal

or Create an Account

Close Modal
Close Modal