One could develop an aneurism, trying to follow the trial of land ownership in the Santa Clarita Valley in the 1850s and 1860s. So, we won't try. There are just too many foreclosure proceedings and too many games of "hide the football" to avoid foreclosure.
What's important here is that around 1858, Jose Salazar, the new husband of Antonio del Valle's widow, borrowed $8,500 from L.A. real-estate mogul and eventual citrus magnate William Wolfskill at 1½ percent monthly interest, compounded quarterly. As collateral, Salazar pledged 6/11ths of the Del Valle family's Rancho San Francisco (known colloquially as San Francisquito). The rancho comprised 48,612 acres of land stretching from Piru on the west to Soledad Canyon on the east. (Eleven is a magic number: Under old Mexican law, ranchos could comprise no more than 11 square leagues. A Mexican league was 4,428 acres.)
By 1860, Salazar couldn't even pay the family's property taxes, much less repay a loan. In 1863, Wolfskill foreclosed on his 6/11ths of the Rancho San Francisco and on the Del Valles' property on the Plaza in Los Angeles. Or at least he tried to.
Whether Wolfskill was ever made whole is a subject for further research. Despite a second attempt at a court-ordered sheriff's sale in 1864 (reported below), Wolfskill did not take possession of the rancho, and the sheriff's sale was not held — or if it was, nothing came of it. By that time, Salazar had already borrowed more money and re-mortgaged the mortgaged property. In March 1865, when the Del Valles sold their rancho to Thomas R. Bard (for $47,519.71), the sale included Wolfskill's 6/11ths stake.
Actually, the Del Valles didn't sell quite all of it. They retained the westernmost 1,350 acres, which became the separate Rancho Camulos when Henry Newhall bought the 46,460 acres that remained of the old Rancho San Francisco at a sheriff's sale in 1875.
Further reading: "Rancho San Francisco: A Study of a California Land Grant" by Arthur B. Perkins, June 1957.