Archeocyathids in the Weisner Quartzite. The specimens are poorly preserved but show the tops of the double-cone structures separated by numerous partitions (septa). Archeocyathids are generally classified as an extinct group of sponges with carbonate skeletons. They have been found in a wide range of shapes, commonly as upright cones, and some formed the earliest reef structures. They are almost entirely restricted to the early Cambrian, approximately 530 to 510 million years ago.
