Routine pollen analysis was performed for 71 sediment samples from Midden Trace "D," and 19 samples from the Los Cerritos Dorm site. Pollen preservation ranges from very poor to excellent, and the pollen concentration is generally low, except for agricultural or landscaping fill. The "Other Compositae" pollen type is the most abundant type at both sites. Pollen and spores of aquatic species are common, and the pollen of exotic plants, including wheat and corn, is present throughout the profiles. Oak pollen is abundant just below the surface at both sites. Based on palynological and other evidence, the upper 2 units at both sites are of historic age. Evidence for prehistoric human activity is most abundant in the "midden" horizon of Midden Trace "D" an in the "alluvial" horizon of Los Cerritos Dorm.
The Midden Trace "D" site is uniquely important due to its stratigraphically-complete sampling density and the presence of unusually high percentages of Liguliflorae and Artemisia pollen. Its pollen profile can be divided into 4 pollen zones: Chenopodiaceae-Amaranthus, Liguliflorae, Artemisia, and Ambrosia. Ecological, palynological, and geological evidence suggests that extensive human disturbance is the cause of the uniquely-high percentages of Liguliflorae pollen from 100 - 280 cm. However, no other known sites have such high percentages of this pollen type, so this conclusion is tentative.
The upper 120 cm of the Los Cerritos Dorm profile ("fill" and "midden" units) is characterized by high pollen concentration, the presence of wheat and corn pollen, generally low charcoal percentages, and similar radiocarbon ages -- indicating that both units are historic fill. The relatively high percentages of Riccia in the "alluvium" unit of the Los Cerritos Dorm profile indicates still, standing water, at least seasonally, when the sediment was deposited. The "alluvium" unit contains moderate indications of prehistoric human activity, and may correlate with the upper Liguliflorae zone of the Midden Trace "D."BACK