by David Medaris at Isthmus.com
"Robert Birmingham was touring Ireland when he had 'a sort of epiphany.' He was visiting megaliths — large, ancient stone structures exemplified by England's Stonehenge. 'It occurred to me,' he recalls, 'that there was a connection between megaliths and the mounds here,' in Dane County [Wisconsin]....Read the whole story about landscape archaeology here.
... the massive earthworks amounted to vast 'cosmological maps,' Birmingham says."
Birmingham's theory supports the theory by Andis Kaulins in Stars Stones and Scholars that such megalithic sites were land survey monuments sited and sighted by ancient astronomy. See also megaliths.net