Though the designs in general remind one of those of the Southwestern Pueblos, as, for instance, the cloud terraces, scrolls, etc., still most of the decorations in question show more delicacy, taste, and feeling, and are richer in colouring.
This kind of pottery is known only from excavations in the valleys of San Diego and of Piedras Verdes River, as Well as from Casas Grandes Valley.

It forms a transition from the culture of the Pueblos of Arizona and New Mexico to that of the Valley of Mexico, a thousand miles farther south.

In a general way the several hundred specimens of the collection can be divided into four groups: (1) The clay is quite fine, of white colour, with a slightly grayish-yellow tinge.

The decorations are black and red, or black only.

This is the predominant type, and may be seen in Plates I.and II.; also Plate III., _a_.
(2) Of a very similar character, but somewhat coarser in texture, and heavier.