On the land owned by Mr. Fish, in Iowa, near the Mississippi River, a short distance below where the Little Iowa joins it, is a group of mounds placed on the crest of a ridge running parallel with the former stream about one-fourth of a mile therefrom. There are in all about thirty of these mounds, circular in form, and varying from 20 to 40 feet in diameter. These are all burial mounds, but one singular feature observed is that those on the higher sandy ground, although about the same size and having cores of clay similar to those on the firm clay portion of the ridge, have a layer of sand, some two feet or more added to them, yet when opened the contents and mode of construction of the two classes were found to be the same, to wit, a layer of hard clay covering decaying human bones, fragments of pottery, and rude stone implements. There were generally two or more skeletons in a mound, which were placed horizontally side by side on the natural surface of the ground. [Illustration: FIG. 8.--Section of mound showing stone vault (Iowa).] Upon the terrace below the group were found the remnants of a row of comparatively large burial mounds. A railroad line having been carried along here, the larger portion of these works were destroyed; still, enough remained to show that the height varied from 6 to 15 feet, that they were composed chiefly of sandy loam similar to that around them, and that each had a hard central core of clay mixed with ashes, usually covering but a single skeleton. The relics found in them when opened consisted chiefly of stone axes, arrow and spear heads, and a few copper celts. In one, which was 32 feet in diameter and 8 feet high and less injured than the others, was a circular vault, walled as represented in Fig. 8. This was built of flat, unworked stones, laid up without mortar, gradually lessening as it ascended, and covered at the top by a single flat stone. In it was a single skeleton in a squatting posture, with which was a small earthen vase of globular form. A singular fact was observed in a group near the town of Peru, Dubuque County. This group is situated on a dry, sandy bench or terrace some 20 feet or more above a bayou which, makes out from the Mississippi. It consists chiefly of small circular tumuli, but at the north end are four oblong mounds varying in length from 40 to 110 feet and in height from 1-1/2 to 4 feet; there is also an excavation about 30 feet in diameter and 6 feet deep, and scattered throughout the group are a number of circular earthen rings varying in diameter from 12 to 30 feet and from 1 to 2 feet in height.