[6][7] With the cession of California to the United States following the Mexican-American War, the 1848 Treaty of Guadalupe Hidalgo provided that the land grants would be honored.

[11] In the 1862 Stockton sold the rancho to Charles B. Polhemus and Henry Newhall, who planned to run railroad tracks through the valley.

A description on the commemorative plaque reads: "Here, on the 1,939-acre Rancho Potrero de Santa Clara, Christopher A. Shelton in early March 1853 introduced the honeybee to California.

In Aspinwall, Panama, Shelton purchased 12 beehives from a New Yorker and transported them by rail, 'bongo,' pack mule, and steamship to San Francisco.

Only enough bees survived to fill one hive, but these quickly propagated, laying the foundation for California's modern bee-keeping industry.