My research on City #7 began when Janey Joyce discovered a newspaper article from about 1910-13 about the downtown poor house property being sold, but the burials in the poor house cemetery were not being moved - just markers removed. The reporter was outraged and told stories of some of the folks buried there to raise awareness of the situation, stating that they were from the 2nd book, as the 1st book of 1000 names was missing. The upshot was City fathers had to move the burials and they were moved to a corner of Pittman Sullivan Park on the East side.
It seems that burials continued in the park until at least the late '20's. Then in the 1940s St.Gerard's Catholic Church was sold the same property upon which to build a High School. When the foundation was dug in the mid 40's, the bones that were uncovered were placed "in a box" and removed to Stinson and/or the area around it. This information was provided by a retired teacher who did his Master's thesis on Pittman-Sullivan Park. He also stated there were burials remaining on the school site, because bones would still occasionally surface. If your ancestors were buried at city #7, they could be in several places.
1 book of City #7 names was found by the San Jose Sexton when pestered by a determined researcher and has been published by the SA Genealogical & Historical Society. If you come across a reference to City #8, that is what San Jose Cemetery was called until the 1920s. Hope this is helpful.