rikingly suggestive of the incipient
pottery made by surrounding a basket with a coating of clay.[88] When it
was discovered how to make the earthen bowl or dish without the basket,
a new era in progress was begun. So when it was discovered that an
earthen wall could be fashioned to answer the requirements of
house-builders without the need of a permanent wooden framework, another
great step was taken. Again the consequences were great enough to make
it mark the beginning of a new ethnical period. If we suppose the
central portion of our continent, the Mississippi and Missouri valleys,
to have been occupied at some time by tribes familiar with the Mandan
style of building; and if we further suppose a gradual extension or
migration of this population, or some part of it, westward into the
mountain region; that would be a movement into a region in which timber
was scarce, while adobe clay was abundant. Under such circumstances the
useful qualities of that peculiar clay could not fail to be soon
discovered. The simple exposure to sunshine would quickly convert a
Mandan house built with it into an adobe house; the coating of earth
would become a coating of brick. It would not then take long to
ascertain that with such adobe-brick could be built walls at once light
and strong, erect and tall, such as could not be built with common clay.
In some such way as this I think the discovery must have been made by
the ancestors of the Zunis, and others who have built pueblos. After the
pueblo style of architecture, with its erect walls and terraced stories,
had become developed, it was an easy step, when the occasion suggested
it, to substitute for the adobe-brick coarse rubble-stones embedded in
adobe. The final stage was reached in Mexico and Yucatan, when soft
coralline limestone was shaped into blocks with a flint chisel and laid
in courses with adobe-mortar.

[Footnote 88: See above, p. 25.]

[Sidenote: Mr. Cushing at Zuni.]

The pueblos of New Mexico and Arizona are among the most interesting
structures in the world. Several are still inhabited by the descendants
of the people who were living in them at the time of the Spanish
Discovery, and their primitive customs and habits of thought have been
preserved to the present day with but little change. The long sojourn
of Mr. Cushing, of the Bureau of Ethnology, in the Zuni pueblo, has
already thrown a flood of light upon many points in American
archaeology.[89] As in t