Shell Mounds

Indigenous people, still present on the land today, densely populated the resource-rich marshes around San Francisco Bay. N. C. Nelson, an archaeologist for University of California, mapped shell mounds that were still intact in 1909.  He noted in his article that many other indigenous resources and structures were not mapped, and that he ran out of time and money before he could survey completely. On this digitized version of his survey points, his records of the large and visible shell mounds attest to the active indigenous people of the Bay Area. Notice that shell  mounds cluster around the edges of wet meadows and tidal salt marshes. 

The historic habitat types are mapped by San Francisco Estuary Institute (BIOS, ds3201) and are a reasonable guess about what the original habitats in the 1800s before colonization. The SFEI data is confined to the inland marshes and omits the coastal areas.