The “soil” could have come from top soil on fields that had municipal wastes applied.
If the material met 503 regulations as a lime stabilized material then that would account for the high pH and the Calcium being elevated.
BTW: municipal wastes are fine materials to use as a liming agent or fertilizer source. Different industries or cities meet federal and state criteria in different ways though all are legal, safe and regulated.
It would also be nice to know the amount you picked up, 8 ton load, pickup truck, 3 yard loader full, tater sack.
McCallum
