This is the entrance to the burrow of a large wolf spider (Geolycosa sp.) These intriguing turrets are erected around the entrance to the burrow and vary in materials used. Here, grains of sand are intermixed with bits of plant matter to create a turret or chimney over the entrance way. The burrow itself is very deep and wide. Other burrow entrances have turrets made of lichens https://pbase.com/image/166247206), and of dried grass https://pbase.com/image/166193245).