A 35-year-old workman was injured fatally yesterday when a section of a decorative granite-block wall collapsed on him in Lutherville as he was digging a ditch beside it so that the wall could be moved.

A MedEvac helicopter flew the victim, Geoff MacLellan of the 1200 block of Fairway Drive, Westminster, to Maryland Shock Trauma Center, where he was pronounced dead.

The accident occurred about 9:30 a.m. at the entrance to Selsed House, the former Marburg estate, in the 1100 block of W. Seminary Ave.

Authorities said Mr. MacLellan was digging a ditch beside the semicircular wall so that cables could be passed beneath it to a crane which would then hoist the wall onto a truck.

The walls were to be moved and reassembled close to the Tudor manor replica mansion because the rest of the estate is being developed for new houses, said Stewart Greenebaum, one of the developers.

Jim Kappes, who used his backhoe to pull the wall off Mr. MacLellan, said the pillar at the end of the wall toppled, pulling the adjacent wall section onto Mr. MacLellan.

Fellow workers pulled the victim free as Mr. Kappes lifted the wall with the backhoe.

Mr. Kappes said the ditch had been dug about 4 feet deep on both sides of the wall. The wall itself was about 25 feet long and tapered in height from about 8 feet near the pillar to about 4 feet at its end.