one of which resembles a huge bird-track with a middle toe 155 feet in length and the remaining two each 110 feet in length—together with the solitude of the ancient forest which entombed this buried city, we confess impressed us with a sense of wonderment and that strange perplexity which an insoluble mystery exercises over the mind. We can appreciate the remark of Mr. Squier in his description: “Here covered with the gigantic trees of a primitive forest, the work truly presents a grand and impressive appearance; and in entering the ancient avenue for the first time, the visitor does not fail to experience a sensation of awe, such as he might feel in passing the portals of an Egyptian temple, or in gazing upon the ruins of Petra of the Desert.” It is estimated that a force of thousands of men assisted by modern appliances and implements as well as horse-power, which the Mound-builder did not possess, would require several months in which to construct these works.[35] At Marietta a most interesting system of works exist, covering an area three-fourths of a mile long and half a mile broad. These occupy the river terrace or second bottom at the confluence of the Muskingum River with the Ohio, and present analogies with the works further south and with those of Mexico.[36] Two irregular squares inclose fifty and twenty-seven acres respectively. The walls of the larger are between five and six feet high and from twenty to thirty feet wide at the base. Within an enclosure are four truncated pyramids or platforms, one of which, the largest, is 188 feet long, 132 feet wide, and only 10 feet high, with a graded way reaching to its summit, as have also two of the other pyramids. No one can look at these structures without seeing the force of Lewis H. Morgan’s Pueblo theory,[37] which makes these mounds or flattened pyramidal elevations the foundation for edifices of a perishable nature; constructed perhaps of hewn wood, but not of a combination of the adobe and wood as he supposes, since no material for such a combination is found in the Ohio valley.[38] The most elevated of the Marietta works is an elliptical mound thirty feet high, enclosed by an embankment. [Illustration: Graded Way near Piketon, Ohio.]