There are 500+ burial sites in Harris County, TX from the large city cemetaries to single gravesites. You will find a partial listing at HARRIS COUNTY CEMETERIES but I'm quite certain that there are many others not listed. (NOTE: The four alphebetized pages are the most up to date - zip, lat/lon and KEY Map are not updated.) There are four web pages which are sorted by ZIP Code, KEY Map page, Alphebetized Cemetery Name and Lat/Lon Coordinates. Use your GPSRs to document the locations of these resting places and any others you can find via genealogical societies, online services, libraries (Clayton), etc.
Your inputs will help Harris County genealogical researchers while you enjoy the hunt. Don't forget, you can only log one find per team and your log must conform to Virtual Cache rules which includes a photo of your gps at the cemetery - uh, cache, of your choice.
For available cemeteries, see the HARRIS COUNTY CEMETERIES page.
GOOD LUCK!! -- GRAVESEEKER