Cataract. Whirlpool sandstone 12/4 Bassel limestone 8 4 Lower grey shale 48 4 Upper red .. 22 Total Cataract 90 pts. On the bottom layer of what here Medina Isaur dolomite pebbles and the Medina- Cataract bivalves. The same bivalves occur immediately in the shale below and in the sandy red layers that at time are distinctly intrafor- motinal conglomeratic. Three foot thick Medina Zinzula Moya give good bivalve clots, and 18 inch beds, these the same bivalves occur plus a vast abundance of dolomite pebbles, and fragments of L. Moya. There is now no doubt that here is no break between the Medina and Cataract. The story well section proves this.