Meet the Hamiltons. Samuel Hamilton is the Irish-born patriarch, and a big, kind man with a knack for inventing useful things that he can't make any money off of.
His wife Liza is a tiny Presbyterian woman with a strict sense of morality and a disdain for all things fun. The narrator has no idea how they ended up together, though they suspect that there was some other woman that Samuel had once been really in love with.
The Hamiltons have just about the worst piece of land in the Salinas Valley, so Samuel keeps his family fed by fixing farm equipment. He's a good talker so people like to go hang out with him.
Samuel is also a natural born midwife, and he's great with the kids.
Liza, on the other hand, is one mean God-fearing mother, who pops out children like it's nobody's business.
People like the Hamiltons came from Europe and snagged up as much land as they could because it was cheap, not because it was good. But some people who already had money bought the really good land—people like Adam Trask.