You may be interested in Ancient Faiths and Modern by Thomas Inman from 1876, newly available over at Project Gutenberg.
“There is, indeed, much more evidence than is generally supposed to connect the ancient mound-builders in America with the inhabitants of the Eastern Hemisphere, particularly in their modes of burial, the nature of their earthworks, and the style of such ornaments and figures as have been found. For example, there is one enclosure described, in the centre of which is erected a mound and pillar, precisely resembling the linga yoni of the East. In addition to these, carved stones have been found, which unite together such Oriental emblems as the sun and moon, the Tau, T and the egg, O which together make the well-known Egyptian symbol A. Again, Domenech figures some male and female human effigies, of whom American savans write that they represent idols of sexual design, similar to those exposed in the Mysteries of Eleusis, one of them being a badly finished image of Priapus.”