widespread and prevalent in both subaerial and submarine exposure in 

 the study area and therefore the most germane to this report. It was 

 deposited during the Wisconsin Glaciation when sea level fluctuated in 

 elevation. Barton (1930) and Pettit and Winslow (1957) describe the 

 Beaumont as consisting of abruptly changing facies of fluvial and deltaic 

 sediments mixed with lagoonal shallow marine deposits and sandy barrier 

 island deposits. The ancient barrier beaches, termed Ingleside, consist 

 of three distinct topographic ridges, inland but roughly parallel to the 

 present coast; these have been correlated with similar features from 

 southern Texas to parts of Louisiana. These old barrier islands gener- 

 ally have relief of about 3 meters and are about 1.6 kilometers (1 mile) 

 wide. Submerged relict Beaumont (Ingleside) barrier beaches present on 

 the gulf shelf have been speculated on in the literature, but no evidence 

 of their presence was found in this study. 



The Beaumont Formation consists of yellow, reddish-brown, grayish- 

 green, and black clays, silty sands, and fine brown sand. Calcareous 

 (caliche) nodules and shell fragments are also sometimes present. The 

 surface of the Beaumont was deeply weathered and eroded during exposure 

 in late Wisconsin-age; consequently, its surface sediment is usually 

 stiff, dehydrated, and multicolored. These characteristics make it 

 relatively easy to identify in outcrop, as well as in the cores taken 

 during this study, except in the vicinity of inlets where deep erosion 

 and subsequent filling by recent sediments has occurred. Because of the 

 sediment's dense character and uneven eroded surface, it generally creates 

 a strong and distinctive acoustic reflector that is traceable on seismic 

 profiles over nearly the entire study area. 



c. Deweyville Formation . Deweyville sediments are late Wisconsin- 

 age and overlie the Beaiunont . Bernard (1950) describes them as clayey 

 silts and silty fine sands with minor occurrences of sand. They are 

 younger than 30,000 years and grade into Holocene-age sediments. Their 

 exposure on land is apparently limited and their presence on the shelf 

 is unknown. 



d. Ho locene -Modern Sediments . Several authors working in different 

 geographic areas have placed the Pleistocene-Holocene boundary at 12,000 

 to 20,000 years ago. This is the time when the world climate moderated 

 and ice sheets from the latest glaciation (Wisconsin) began to melt and 

 release water to the ocean basins with a consequent elevation of sea 

 level to the present level. 



This rise in sea level is shown in Figure 10, which depicts a steady 

 rise until about 4,500 years ago at which time the curve changed to a 

 more gradual slope. The time from about 4,500 years ago to the present 

 is termed modern. Presently, sea level in relation to land at Galveston 

 is rising about 40 centimeters (1.4 feet) per century (Hicks, 1972). 

 This figure is based on measurements taken from 1940 to 1970, and is 

 complicated by documented subsidence in the Galveston region due to both 

 natural and man-induced causes. The Holocene and modern sedimentary 

 deposits along the Texas coast consist of fluvial flood plain and deltaic 



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