According to this chart by Robert Anderson of beach-bum toilet Pepperdine, law-school applicants who majored in mathematics, physics, biomedical engineering, classics, or linguistics on average score above 160 on the LSAT, whereas those in such illustrious fields as criminology, criminal justice, family relations and child development, social work, and elementary education score below 150.
The majors on the Cooleyite end of the range generally seem more closely connected to law than those that approach Harvard's territory. Selection bias may account for part of that effect: maybe the would-be mathematicians and classicists who decide to apply to law school are the crème de la crème, whereas just about every dipshit in "criminology" (which as a major is scarcely better than underwater basketweaving) decides "I's gonna be a loyer!" and brings down the average LSAT score. It's a safe bet, though, that criminology and such don't attract the brightest students. Only in recent years have I even heard of majoring in criminology.
In addition, those majors at the top produce only a tiny handful of applicants. The dumb masses in criminal justice and elementary education drag the average down, down, down.