Stone mortars were among the most common and most useful implements that the ancient inhabitants of the land possessed, being used for the preparation of meal and for other purposes. Correspondingly numerous therefore are these objects, found mostly in fragments, and scattered through nearly all the strata from the second to the tenth. There are three perfect specimens and eleven fragments in our collection, nearly all made of lava. The largest of the mortars, 1-9102, fig. 3, was recovered quite accidentally near g in plan III at the extreme western end of the mound. Judging from the place of its discovery, about 3-1/2 inches below the surface, the mortar must have been lost in about the middle period while the foot of the mound was increasing from n to p. Its outside surface is rough like the natural boulder, it is 1 foot long by 9 inches wide and 7-1/2 inches high. Within it is oval and measures 6 to 7 inches in diameter and 5 inches in depth. The smaller mortar, 1-8705, fig. 4, was found in stratum VI. On the outside it is rounded off and ornamented with engraved vertical lines, which are intersected near the edge by a horizontal one. The edge is partly worn away by use. Such simple lines as an ornamentation of the outside are occasionally observed on California mortars.
Fig. 3. × 1/4. A large mortar.
1-8664, fig. 5, a small mortar from stratum III, is of different shape, oval both in its outline and in cross section, the bottom being slightly flattened; it has a rather small round cavity, 1-1/2 inches in diameter and one-sixth inch deep. It may have served for the pounding up of substances which were used only in small quantities, such as color pigments. The width of this mortar is 2-1/2 inches, its height and thickness 1-7/8 inches. Powers presents a view of a similar specimen from California, a proof that this type occurred in this region. A fragment, 1-8810 of the collection from stratum VIII, may be the bottom of a similar utensil.
Fig. 4. About one-half natural size.
Fig. 5. × 3/4. Small mortars.
Some additional types of mortars are represented among the fragments; they will be given below in the order in which they were recovered. 1-8594, fig. 6, from stratum II, is one of several fragments of this stratum and belongs to a relatively advanced type, resembling a vessel. These stone vessels had a fairly even thickness of the sides of about an inch, and were fashioned quite regularly without and within. This rim is flattened and slopes inward. The diameter of the complete mortars may have been a foot. This type of mortar is quite common in California. The collection from Santa Rosa Island in the University Museum made by Dr. Jones contains several similar specimens. 1-8707 fig. 7, stratum IV, is an odd fragment. Its well fashioned bottom part is surrounded by a rim which in turn is bordered by two chambers which exactly correspond; the surface between them is broken. This fragment may also have been part of a mortar, although it is not possible now to restore it to any shape represented among the familiar types. Fig. 8, 1-9077, shows a fragment of a mortar recovered in the Xth stratum, and it is the only one found lower than stratum VIII. It lay hardly an inch from the base of the mound. It has a peculiarly jagged shape; the convex exterior is the rough boulder stone, as are the uneven sides, but the inner concave surface is ground down smooth. The peculiar jagged shape may be explained by the fact that it is a piece of a mortar, the rim of which by long usage had been worn away in places, and as a result points were formed. The collection of Dr. Jones from Santa Rosa contains a mortar with a jagged rim, caused probably also by wearing away, but in that case the points of the rim show some decoration, unlike the present fragment. 1-8848, fig. 9, stratum VIIa, may throw some light on the possible cause of these indentations resulting from long usage. In the latter specimen the surface of the bulging portion is rough, as in 1-9077.
