Owing to the fact that we have today only the pearly nautilus, a still little known deep-sea form, for comparison, there still exists much doubt in regard to the mode of life of the Paleozoic Nautiloidea. To cite an example, the simple straight-shelled Orthoceras is considered by some good authorities to have been a bottom crawler, by others as having swum in a vertical position, and by still others as having buried himself in the mud in an upright position, or as having been fixed at the apex. There are few facts known that could shed light on the mode of life of these early cephalopods, and it is therefore thought worth while to record here some new biologic observations on these creatures.
The Trenton limestone of New York has afforded a number of specimens of Orthoceras (Geisonoceras) tenuitextum . . .