Archfiends use a methodical background for exhumation of cordinates(sic).
Cache is at N51 1P.TCE W 00 1C.YCT
To further add to the fun, each geocheck (1 to 4) has a clue in it. You will need the 4 clues plus the 4 clues from HortonHunter's Mists of Time series to solve our grand finale combined cache - ENDGAME. They form a logic puzzle, which is to be found on the ENDGAME page.