Gammell married Jane McDaniel, a native of New York, on July 19, 1839 in Houston. The couple had no children. In 1842 Gammell was again called to defend his new homeland and enlisted in Captain James Gillespie’s company in the spring of that year to defend San Antonio against an invasion by the Mexican Army. He again took up arms in September of 1842 and fought under Captain Jesse Billingsley against the Mexican Army at the Battle of Salado Creek.
Gammell traveled to California during the gold rush, but returned to Texas to settle on 390 acres just outside the city limits, now situated in Houston’s Fifth Ward.He opened a gunsmith shop on Congress Avenue in Houston around 1851 and operated the business until his retirement in 1866. Gammell died unexpectedly from pneumonia on April 10, 1869 and was buried in Houston’s Masonic Cemetery. In 1900 he was reinterred in the Deutsche Gesellschaft (German Society) Cemetery, which is now Washington Cemetery.
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