Steve Brooker, 6 ft. 5 in. former professional skateboarder, sub-3-hr.-marathon runner, survivor of multiple strokes and the self-appointed tutelary spirit of the Thames, thinks he has found something. To me it looks like mud, but I'm not in a position to argue. Brooker, 48, is a member of the Mudlarks, a society of amateur archaeologists who are licensed by the Port of London Authority to scavenge the banks of the Thames for historical artifacts. Because of Brooker's oversize frame, his talent for major discoveries and his overall awesomeness, he is known by admirers as the Mud God.