. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. CRETACEOUS STRATIGRAPHY OF SAN NICOLAU AND SALINAS, ANGOLA 249 Immediately below this fossiliferous horizon is a bed rich in stromatolites. This deposit has, therefore, all the features of a classical condensed sequence, as recorded by Rod (1946), Jenkyns (1971) and others, viz. faunal enrichment and faunal mixing, negligible thickness and widespread distribution, and associated stromatolitic algae. Sedimentological evidence supports this, since in the coastal cliffs west of San Nicolau about 25 m of
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. CRETACEOUS STRATIGRAPHY OF SAN NICOLAU AND SALINAS, ANGOLA 249 Immediately below this fossiliferous horizon is a bed rich in stromatolites. This deposit has, therefore, all the features of a classical condensed sequence, as recorded by Rod (1946), Jenkyns (1971) and others, viz. faunal enrichment and faunal mixing, negligible thickness and widespread distribution, and associated stromatolitic algae. Sedimentological evidence supports this, since in the coastal cliffs west of San Nicolau about 25 m of limestones and silts are seen to separate the volcanics from the unfossiliferous red sands, whereas the measured section in the gully totalled 14 m, while the Upper Cenomanian at Salinas was at least another 8 m. Howarth's fauna is, without question, from the same horizon which must be considered a condensed sequence spanning Turonian to lowest Goniacian times. m Red. sandstones ^ V I Basaltic rocks v.^(^Vrj Limestones Red siltstones Fig. 2. Geological section through the west side of the Jombovacai valley, about 2 km north of the Posto de San Nicolau (for explanation see text). Deposition of this stratum was followed by a period of emergence and the eruption of the alkali-basalts. The presence of a disconformity between these beds and the basalts is evident in the section exposed in the western side of the Jombovacai valley (see Fig. 2) about 2 km north of the Posto de San Nicolau. Here, 3 m of highly fossiliferous white limestone, unfortunately lacking in ammonites, are crammed with bivalves and gastropods with their recrystallized shells preserved. These are overlain by 0,28 m of unfossiliferous maroon silts succeeded by 1,05 m of hard red limestone, unlike any exposed in the coastal. 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
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
