Cool! This is a female foldingdoor "tarantula," Antrodiaetus sp., family Antrodiaetidae. Look for the burrows in dry, sheltered spots in forests. The tunnel is vertical, looks bottomless, and lined with silk that forms a turret above the surface. The spider will sometimes close the "doors" of each side of the turret so they meet in the middle, like kitchen cabinets. These are primitive spiders that still bear traces of segmentation on the abdomen (note the single "sclerite" near the base of the abdomen on this specimen). Males have three sclerites, and are easily collected in the fall with pitfall traps. These can be pretty large spiders.