 Four overlapping ecological regions have been identified on the Table Rocks , with considerable differences in the variety of wildlife found in each . From the outermost base of the rocks , three regions consisting of oak savanna , chaparral , and mixed woodland surround the relatively flat tops . The andesite cap is covered by the fourth region , mounded prairie . This region formed when the caps were slowly eroded by the freezing and thawing of water that seeped into the ground ( ice erosion ) , which created layers of mounded soil . Vernal pools fill in from October to June in the mounded prairie area due to the andesite 's impermeability . The pools support species of plants and animals . 
