One of us remarked last year in an article in Science Progress that “we may expect to find our Carboniferous deposits divisible into zones in a manner comparable with that which holds good among other … strata.” The same writer called attention to the fact that similar views had been expressed by Waagen (Salt Range Fossils, “Memoirs of the Geological Survey of India, 1891”), who considered that the Carboniferous fossils had not received the same attention as those of other rocks.