UNAUTHORIZED RWY ENTRY XING OP.

Narrative

AS WE TURNED OFF OF RWY 30 AFTER LNDG; TWR OR GND ADVISED US TO HOLD SHORT OF 25R ON DELTA. I WAS NOT AWARE THAT WE WERE ALMOST IMMEDIATELY AT THAT INTXN AFTER TURN OFF. I SUSPECT IT WAS A CASE OF THINKING I HEARD WHAT I EXPECTED TO HEAR AS; IN MY MIND; I THOUGHT I WAS TO HOLD SHORT OF THE RWY WE HAD JUST LANDED ON (30). I CROSSED WHAT I THOUGHT WAS A TAXIWAY (AND IT WAS CLR OF TFC) AND WAS TRYING TO LOCATE DELTA WHERE IT INTERSECTED 30. THE COPLT WAS APPARENTLY ALSO CONFUSED AND WAS LOOKING FOR HIS MAP OF THE ARPT. NEITHER OF US SAW ANY RWY 25R MARKING SIGNS. GND CALLED AND ASKED IF WE WERE ON RWY 25R. BY THAT TIME OF COURSE WE HAD REALIZED OUR ERROR. IN RETROSPECT; IT WAS A CASE OF NOT THOROUGHLY FAMILIARIZING OURSELVES WITH THE MAZE OF CRISS-XING RWYS AT LGB; AND A PREDISPOSITION TO 'HEAR' WHAT YOU EXPECT TO HEAR. FORTUNATELY THERE WAS NOT A REAL SAFETY CONFLICT. I ALSO THINK; DUE TO THE IMMEDIATE PROX OF RWY 25R AT THE 30 TURNOFF; GND MIGHT HAVE BEEN MORE HELPFUL HAD THEY SIMPLY TOLD US TO HOLD OUR POS ON DELTA WHICH WAS SHORT OF 25R.