I am researching Thomas Pilkington found first in the 1870 Santa Cruz, California census: Thomas Pilkington 55 yo  b. Eng Caroline M. Pilkington 45 yo  PA Thomas Pilkington 13 yo  CA Rebecca Pilkington 9 yo  CA James A. Pilkington 6 yo  CA
Based on this census record, I would expect to find the family in California in 1850. But I've not found them anywhere at all - not even in CA.
In 1880 the family was still in Santa Cruz County: Thomas Pilkington 64 yo b. Eng Mary Pilkington 45 yo b. NY - parents born NY Thomas J. Pilkington 22 yo b. CA - father b. ENG; mother b. PA Rebecca Pilkington 18 yo b. CA - father b. ENG; mother b. PA James Pilkington 17 yo b. CA - father b. ENG; mother b. PA
This census seems to indicate that Thomas' wife, Caroline, has died and that he has m2 Mary. She is not the mother of his children.
Does anyone know anything of this family? Especially who was Caroline? Where did Thomas live before arriving in California?