A catastrophic landslide 22,500 years ago dammed the upper reaches of northern California's Eel River, forming a 30-mile-long lake, which has since disappeared, and leaving a living legacy found today in the genes of the region's steelhead trout...about 60 miles southeast of Eureka. The river today is 200 miles long, carved into the ground from high in the California Coast Ranges to its mouth in the Pacific Ocean in Humboldt County. The evidence for the ancient landslide, which, scientists say, blocked the river with a 400-foot wall of loose rock and debris ... "Perhaps of most interest, the presence of...