The statements of these early writers have been abundantly confirmed, respecting the existence of monumental remains and traces of civilized life, by the patient explorations of such workers as Schoolcraft, Squier, Davis, Pidgeon, and others, who have opened up many of these half-concealed monuments and disclosed their contents. Squier, in speaking of those found along the Ohio Valley, says, "The British Islands only afford works with which any comparison can safely be instituted. The 'ring-forts' of the ancient Celts are nearly identical in form and structure with a large class of remains in our own country." The same author has given some deeply interesting accounts in his "Aboriginal Monuments" of his explorations of mounds, his finding human skeletons in rude frame-works of timber, instruments and ornaments of silver, copper, stone, and bone, sculptures of the human head, pottery of various kinds, and a large number of articles, some of which evince great skill in art. He says, "In every instance falling within our observation, the skeleton has been so much decayed that any attempt to restore the skull, or indeed any portion of it, was hopeless. Considering that the earth around these skeletons is wonderfully compact and dry, and that the conditions for their preservation were exceedingly favorable, while in fact they are so much decayed, we may form some estimate of their remote antiquity. In the barrows and cromlechs of the ancient Britons, entire and well-preserved skeletons are found, although having an undoubted antiquity of eighteen hundred years." There is, however, no safe rule by which to judge the antiquity of human skeletons by the surroundings. Some have been kept in a wonderful state of preservation under apparently the least favorable conditions, while others have crumbled to dust when it was thought they ought to have been preserved. It must be borne in mind that these mounds bear no resemblance to Indian burying-grounds. They are the sepulchres of a superior people. In 1844 a gentleman in Ohio sent to the librarian of the American Antiquarian Society, Worcester, Massachusetts, a cross, the emblem of the Christian faith. It was made of silver, and was about two and a half inches long. It was found on the breast of a female skeleton which was dug from a mound at Columbus, over which a forest of trees had grown. On this cross the capital letters I. S. are perfectly visible. These initials are interpreted to mean the sacred name, Iesus Salvator.