FLC EXCEEDS 250 KT ARR SPD RESTR BELOW 10000 FT IN CANADIAN AIRSPACE.

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DSNDING THROUGH 8500 FT MSL CTR/APCH ASKED FOR AIRSPD WHICH WAS 330 KTS. ASKED US TO SLOW TO 230 KTS AND TURN R TO 040 DEGS (ABOUT 50 DEG R TURN) THAT WE WERE FOLLOWING TFC TO OUR 1 O'CLOCK. WE RPTED SEEING THE TFC AND THE ARPT. HE WAS ON STRAIGHT-IN; COMPANY B757 DSNDING OUT OF 7000 FT. WE WERE STOPPED AT 8000 FT. HE CROSSED IN FRONT BELOW AND WE WERE CLRED TO FOLLOW HIM ON VISUAL. BOTH LANDED NO PROB. PROB CAME FROM MY INTERP OF CANADIAN AIRSPD LAWS. ENRTE FROM LAST STOP I REVIEWED OUR ENRTE REF PAGES AND CONFUSED THE DEP LAWS ALLOWING FASTER THAN 250 KTS BELOW 10000 FT MSL WITH THE ARR SPD LIMITS OF NOT MORE THAN 250 KTS BELOW 10000 FT. I KEYED ON NOT MORE THAN 200 KTS BELOW 3000 FT AGL OR WITHIN 10 NM OF THE ARPT. PASSING 10000 FT ON DSCNT MY FO QUESTIONED THE AIRSPD AND I CONFIDENTLY MENTIONED WHAT I HAD UNKNOWINGLY MISINTERPRETED. NO OTHER CONVERSATION WITH CTR-APCH BUT THERE WAS ENOUGH QUESTION IN MY MIND TO REVIEW THE ENRTE REF THE NEXT MORNING AND DISCOVERED MY MISTAKE. CONTRIBUTING FACTORS WERE THE LAST 15 MINS OF A 12 HR; 4 LEG ON DUTY DAY FINISHING AT XA30 AM BODY TIME. MY FO DID WHAT HE WAS SUPPOSED TO DO -- TALK ABOUT ANYTHING THAT DIDN'T LOOK RIGHT TO HIM. I DID START THINKING ABOUT IT AGAIN WHEN HE BROUGHT IT TO MY ATTN AND WAS PROCESSING IT WHEN CTR-APCH CAME INTO THE PICTURE. I CAN HELP AVOID A SIMILAR SIT AGAIN BY BEING MORE VERBAL; CONVERSIVE EARLIER IN THE FLT. IF I WOULD HAVE DISCUSSED IT WITH MY FO DURING CRUISE; I WOULD HAVE PROBABLY MADE THE RIGHT DECISION BEFORE DSNDING THROUGH 10000 FT.