Colonel Norris opened a number of the ordinary small burial mounds found on the bluffs and higher grounds of Pike and Brown Counties, Illinois, which were found to be constructed in the usual method of this district; that is, with a layer of hard, mortar-like substance, or clay and ashes mixed, covering the skeletons. The positions of the skeletons varied, as we have seen is the case in other localities. The number of intrusive burials was unusually large here. In a number of cases where there were intrusive burials near the surface, no bones, or but the slightest fragments of the bones of the original burial, could be found, although there were sure indications that the mounds were built and had apparently been used for this purpose. These mounds also present evidence of the intrusion of an element from one people into the country of another. On the farm of Mr. Edward Welch, Brown County, Illinois, is the group of mounds shown in Fig. 16. This consists of conical and pyramidal mounds, and the small earthen rings designated house sites. The form of the larger mounds is shown in Fig. 17. Although standing on a bluff some 200 feet above the river bottom, it is evident at the first glance that these works belong to the southern type and were built by the people who erected those of the Cahokia group or farther south. No opportunity was allowed to investigate the burial mounds or house sites, but slight explorations made in the larger mounds sufficed to reveal the fire-beds so common in southern mounds, thus confirming the impression given by their form. It is probable that these mark the point of the extreme northern extension of the southern mound-building tribes. A colony, probably from the numerous and strong tribe located on Cahokia Creek around the giant Monk's mound, pushed its way thus far and formed a settlement, but, after contending for a time with the hostile tribes which pressed upon it from the north, was compelled to return towards the south. [Illustration: FIG. 17.--Forms of larger mounds of the group shown in Fig. 16.] Passing to the northeastern portion of Missouri, which, as heretofore stated, we include in the North Mississippi or Illinois district, we find a material change in the character of the burial mounds, so marked, in fact, that it is very doubtful whether they should be embraced in the district named. Although differing in minor particulars, the custom of inclosing the remains of the dead in some kind of a receptacle of stone, over which was heaped the earth forming the mound, appears to have prevailed very generally. The region has been but partially explored, yet it is probable the following examples will furnish illustrations of most of the types to be found in it. From an article by Messrs. Hardy and Scheetz in the Smithsonian Report for 1881,[23] we learn the following particulars regarding the burial mounds of Ralls County: