Regarding the inhabitance of living creatures in the deepness of the paleonzoic ocean: Towards the end of the Paleozoic era, 90% of the marine forms of life in the archibenthal region of the sea became extinct, which was the biggest recorded mass obliteration of marine life in the history of the earth.

The continental slope; the sea floor from the edge of the continental shelf to the continental rise: The archibenthal zone refers to the ocean layers between 200 feet and 3300 feet (65 and 1050 meters) and is the upper part of the abyssal zone.