Had the materials placed at the disposal of primitive peoples been as uniform as are their wants and capacities, there would have been but little variation in the art products of the world; but the utilization of a particular material in the natural state gives a strong bias to artificial products, and its forms and functions impress themselves upon art products in other materials. Thus unusual resources engender unique arts and unique cultures. Such a result, I apprehend, has in a measure been achieved in North America. In a broad region at one time occupied by the mound-building tribes we observe a peculiar and an original effort--an art distinctive in the material employed, in the forms developed, and to some extent in the ideas represented. It is an age of shell, a sort of supplement to the age of stone. It is not my intention here to attempt at extended discussion of the bearings of this art upon the various interesting questions of anthropologic science, but rather to present certain of its phases in the concrete, to study the embodiment of the art of the ancient American in this one material, and to present the results in a tangible manner, not as a catalogue of objects, but as an elementary part of the whole body of human art, illustrating a particular phase of the evolution of culture. This paper is to be regarded simply as an outline of the subject, to be followed by a more exhaustive monograph of the art in shell of all the ancient American peoples. Art had its beginning when man first gathered clubs from the woods, stones from the river bed, and shells from the sea-shore for weapons and utensils. In his hands these simple objects became modified by use into new forms, or were intentionally altered to increase their convenience. This was the infancy, the inception of culture--a period from which a tedious but steady advance has been made until the remarkable achievements of the present have been reached. Rude clubs have become weapons of curious construction and machinery of marvelous complication, and the pebbles and shells are the prototypes of numerous works in all materials. Rude rafts which served to cross primeval rivers have become huge ships, and the original house of bark and leaves is represented by palaces and temples, glittering with light and glowing with color.