The pattern of decreasing pollen concentration and increasing percentage of deteriorated grains with depth indicate progressive deterioration. However, historic markers are mostly restricted to the top three samples indicating that the site is moderately well stratified. The increased abundance of Erodium cf. cicutarium, Sporormiella, Thecaphora, fungal spores, and Cruciferae place the historic horizon (ca. 200 years ago) at 20 cm. The greater percentages of Cheno.-Amar. pollen below 30 cm support this age determination a similar change is recorded at nearby San Joaquin Marsh.
However, no Eucalyptus pollen was recovered in the surface sample, indicating that the modern vegetation is not fully represented, and the radiocarbon date for the 0-10 cm interval is older than the pollen-based age for the 20-30 cm interval.BACK