▁an ▁ox - hide ▁by ▁the ▁ge ograph er ▁Stra bo . ▁ ▁About ▁three ▁qu arters ▁of ▁that ▁rough ▁oct agon ▁is ▁the ▁Mes eta ▁Central , ▁a ▁vast ▁plate au ▁r anging ▁from ▁ 6 1 0 ▁to ▁ 7 6 0 ▁m ▁in ▁alt itude . ▁It ▁is ▁located ▁approximately ▁in ▁the ▁centre , ▁st agger ed ▁slightly ▁to ▁the ▁east ▁and ▁t ilt ed ▁slightly ▁toward ▁the ▁west ▁( the ▁conventional ▁centre ▁of ▁the ▁I ber ian ▁Pen ins ula ▁has ▁long ▁been ▁considered ▁G eta fe ▁just ▁south ▁of ▁Madrid ). ▁It ▁is ▁ring ed ▁by ▁mountains ▁and ▁contains ▁the ▁sources ▁of ▁most ▁of ▁the ▁rivers , ▁which ▁find ▁their ▁way ▁through ▁g aps ▁in ▁the ▁mountain ▁bar riers ▁on ▁all ▁sides . ▁ ▁Coast line ▁The ▁coast line ▁of ▁the ▁I ber ian ▁Pen ins ula ▁is ▁, ▁ ▁on ▁the ▁Mediter rane an ▁side ▁and ▁ ▁on ▁the ▁Atlantic ▁side . ▁The ▁coast ▁has ▁been ▁in und ated ▁over ▁time , ▁with ▁sea ▁levels ▁having ▁ris en ▁from ▁a ▁minimum ▁of ▁ ▁lower ▁than ▁today ▁at ▁the ▁Last ▁Gla cial ▁Max imum ▁( L GM ) ▁to ▁its ▁current ▁level ▁at ▁ 4 , 0 0 0 ▁years ▁B P . ▁The ▁coast al ▁sh elf ▁created ▁by ▁sed iment ation ▁during ▁that ▁time ▁remains ▁below ▁the ▁surface ; ▁however , ▁it ▁was ▁never ▁very ▁extensive ▁on ▁the ▁Atlantic ▁side , ▁as ▁the ▁contin ental ▁sh elf ▁dro ps ▁rather ▁ste ep ly ▁into ▁the ▁depth