This map was really hard to conform using present-day landmarks.
Not only has sea-level risen considerably in the past 112 Years; but much of the coast line noted in the Coastal Survey has eroded, or used as fill, to erase much of what was open water along the San Francisco Bay Area Shorelines.
This is something that was especially noted in later studies of Bay Area Shellmounds: the possibilty that a mound which had been observed in 1908, was probably lost to the sea by erosion, before the 1970’s and 1980’s.
The changing topography of the Coasts, rising sea level, and dredging and landfill (among other things) have made it futile to argue about some places, like West Berkeley; where no one has a good idea of where the West Berkeley Shellmound actually was, despite the address of Second & Hearst given to it.
People would rather argue over the location of Strawberry Creek, and it’s accompanying marsh instead of taking another hour or two to just read the studies, and find the specific location.
Other mounds did not have the luxury of being named specifically. For instance, the Fernandez site, a shellmound situated in the Rodeo, California area, a little South-West of Martinez, California did have a partial coordinate address mentioned. But, when the coordinated are viewed, the location hovers over the waters off San Pedro Point.
There is also another mound, which was located in the bay, around where Midshipman Point is, which is just gone. No mention of whether the mound was actually standing in 1908, whether it was covered by water, or used to fill the area south of California State Route 37, where it meets the Lakeville Highway.
Furthermore, trying to rectify Nelson’s map to the shoreline of the interior of the San Francisco Bay Area was even more difficult, considered about half of the shorelines are artificial. That is: the shorelines have either been filled or dredged, and do not match the historic shorelines. This made it very hard to judge the specificity of the locations of the shellmounds mapped by Nelson.
But, by using 29 control points, I’ve managed to rectify the map to the best of my ability.