globigerina mud

Geol.: A light-colored calcareous mud in places in the Atlantic 3,000 fathoms deep, and abounding in Globigerine, rich in siliceous sponges, and often supporting a varied fauna of Mollusca, Crustacea, and Echinoderms. Prof. Thomson believed it to be not merely a chalk formation, but a continuation of what is technically called the Cretacean form a tion, the Atlantic having apparently occupied the same geographical situation during the long period since the chalk was laid down.