. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. SEDIMENTATION AND DEVELOPMENT OF LAKE ST LUCIA 99. Fig. 4. Distribution of cross-bed azimuths in the lower nearshore facies of unit 2 (34 readings) UNIT 3 Renewed advance of the sea above its present level planed both aeolian and beach deposits along a seaward-sloping surface at present preserved between 5,3 and 3,4 m. This wave planed surface is mantled by a coarse-grained con- glomerate (Fig. 5) which fills in karst depressions and potholes produced by marine abrasion. The thickness of this conglom
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. SEDIMENTATION AND DEVELOPMENT OF LAKE ST LUCIA 99. Fig. 4. Distribution of cross-bed azimuths in the lower nearshore facies of unit 2 (34 readings) UNIT 3 Renewed advance of the sea above its present level planed both aeolian and beach deposits along a seaward-sloping surface at present preserved between 5,3 and 3,4 m. This wave planed surface is mantled by a coarse-grained con- glomerate (Fig. 5) which fills in karst depressions and potholes produced by marine abrasion. The thickness of this conglomerate, designated unit 3, is therefore highly variable, ranging from a few cm to 2 m. The inclusions consist of locally eroded clasts of calcareous sandstone together with a variety of extrabasinal pebbles. Of the latter quartzite pebbles are most numerous followed by lydianite and gneiss. Some of the inclusions are of boulder dimensions, the largest encountered measuring 65 cm in diameter. The mean diameter is approxi- mately four times greater than that of the pebbles in unit 2. A discoidal shape predominates. Large numbers of oysters and other abraded mollusc fragments are present locally. Some oysters are preserved in living position in potholes. Unit 3 is ascribed to transgressive shoreline processes which charac- teristically deposit coarse shingle. The fact that the coarsest material is preserved in the potholes suggests that these pebbles and boulders were responsible for their abrasion. The sides of some potholes are distinctly undercut. Vigorous. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original South African Museum. Cape Town : The Museum
Size: 1488px × 1679px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
