Early Observations of the Cahokia Mounds
On his last visit to Cahokia the writer stood on the highest platform of the great mound and saw the smoking stacks of East St. Louis only half a mile away. The Cahokia group lies between East St. Louis, on the west and Collinsville on the east, between the Mississippi River and its bluffs, on an alluvial plain at this point eight miles wide. Both cities are enjoying great industrial prosperity and are rapidly growing together. Their junction may in a few years efface one of the greatest earthworks of prehistoric America.
Dimensions of the Cahokia Mound There are in the Cahokia group no fewer than half a hundred mounds, many of them in a remarkably fine state of preservation. They are of different shapes and sizes — square, rectangular, round, and oval. In their present state of erosion they vary in height from four to one hundred feet. Brackenridge, who visited them in 181 1, describes them as "resembling enormous haystacks scattered through a meadow." 1 Among the least eroded are the "Twin Mounds", one of which rises to a sugar-loaf peak while the other has a round top with a scalloped border like the large end of a conch shell.
In a central position dominating the group is the great tumulus known locally as the "Monks' Mound." It is rectangular in form. According to the survey by William McAdams (results published in 1883), the base dimensions are 998 feet from north to south by 721 feet from east to west. It covers an area therefore of about 16 acres. Later surveys have assigned respectively 1,080 and 1,010 feet as the length, and 710 feet as the width. The difficulty of determining the line of junction of the lower edge of the mound with the level of the plain is chiefly responsible for the variation. The mound is built in a series of four receding platforms, the highes hich is ioo feet (97 feet and 104 feet in the later surveys) above the ground level and whose arrangement and relative dimensions can be better under- stood from the illustration accompanying this article than from a table. The mound is strictly oriented with the longer side of the base in a right north-south line. The lowest terrace extends entirely across the southern face, and to the east of the center there is a projecting point which may originally have been a graded approach. The long north-south terrace on the west is badly gullied, and a modern road leading to the top of the mound cuts off one corner. In spite of years of erosion however, all out- lines are surprisingly clear.
Powell Mound at Cahokia Being Destroyed This type of truncated pyramidal structure was named by Squier and Davis, the pioneers in this field, the "temple mound/' 2 Cahokia then Would be most nearly allied with the teocallis of Mexico, and it has been conjectured that on the highest platform of the Illinois mound burned the eternal fire to the sun god as on Tolula and Teotihuacan. Furthermore, Cahokia, because of its huge dimensions and the regular beauty of its construction, deserves comparison with the pyramids of Egypt as well as With those of Mexico. There was, however, no stone used in its building; It is merely a great heap of drift clay and sandy loam. Cahokia, El Sol at Teotihuacan, and Khufu at Gizeh are all straight with the points of the compass. Their base areas are respectively sixteen, thirteen, and thirteen acres, with base dimensions 998 by 721 feet, 761 feet square, and 756 feet square. Cahokia is 100 feet high, El Sol 216 feet, and Khufu 481 feet. The great tumulus has never been explored. Mr. Thomas T. Ramey, who purchased the land fifty years ago and whose heirs still own it, took great pride in his possession of this impressive monument of antiquity, fenced it off from his cultivated fields, and carefully guarded it from the sacrilegious spades of relic hunters. His sons have likewise taken care that it should suffer from neither plow nor mattock. The "big mound" at St. Louis con- tained a large sepulchral chamber in its interior, but whether Cahokia has such a secret to reveal is yet unknown. That there was an extensive burying ground about it was discovered when Mr. Ramey, in ditching the field to the east, dug down through a deep stratum of human bones.
The English geologist, Featherstonhaugh, described the mounds in his book "Excursions Through the Slave States." 9 In 1883 William McAdams 6 N. M. Fenneman (Geology and Mineral Resources of the St. Louis Quadrangle, U. Sdescribes the mounds as mainly remnants of a former valley filling, the smaller ones of gentle slope and oval form being entirely natural. To the larger ones he assigns a composite origin. "To a height of 35 feet above its base the material of Monks' Mound shows assortment and stratification, which is evidently natural. Above that height it affords no structural evidence bearing on the question whether it is of natural or artificial origin; but the form plainly indicates the work of man, and not of geologic processes. It is highly probable that the mound in its natural condition was much lower and broader than at preset, and was of rounder, almost drumloidal form, similar to the smaller ones of the group which now surround it." It should however be pointed out that a number of the smaller mounds have been opened revealing a fire-hardened altar or a decayed burial chamber at the center. The evidence of borings made has been variously interpreted, and the borings themselves do not appear to have been sufficily deep or numerous to warrant a positive conclusion.