Retired Army Maj. Gen. Ernest N. Harmon, 85, a former cavalry officer who became one of the most heavily decorated armor commanders of World War II, died Tuesday at the Veterans Administration Hospital in White River Junction, Vt.

A hospital spokesman said the general died of pneumonia as a consequence of pre-leukemic bone marrow.

"Old Gravel Voice," as Gen. Harmon was known to his troops, once said that tank breakthroughs were costly in armor but relatively cheap in lives. He demonstrated this principle in North Africa, Italy and Northern Europe.

In the process, he earned a Distinguished Service Cross, four Distinguished Service Medals, a Silver Star, and three Legions of Merit.

He was commissioned in the cavalry following his 1917 graduation from the Miliatry Academy at West Point. As an officer in the 2nd Cavalry Regiment, Gen. Harmon participated in the last house cavalry engagements in U.S. Army history during the St. Mihiel and Meuse-Argonne campaigns of World War I.

In World War II, Gen. Harmon led the 2nd Armored Division, "Hell on Wheels," in the November 1942 invasion of French North Africa. In that operation, he earned the Silver Star for directing the unloading of ships under heavy enemy fire and a Distinguished Service Medal for crossing a defended bridge to inform the enemy that an armistice had been signed between the Allies and French North African forces.

He commanded the 1st Armored Division from May 1943 to July 1944 in North Africa and Italy.

In Tunisia, Gen. Harmon personally scouted German forces holding up his troops. He received a Distinguished Service Cross for his exposure to intense enemy fire and then leading his unit in a new advance.

In Italy, Gen. Harmon led the 1st Armored at Cassino and later in the break-out from the Anzio bridgehead. The 1st Armored Division was the first to cross the Tiber River and entered Rome in June 1944.

He took command of the 2nd Armoured Division again in October 1944. It was one of three divisions that led the drive into Germany from Northern France and Belgium. The 2nd Armored broke the Siegried Line above Aachen, then fought in the Battle of the Bulge from December 1944 to January 1945. Gen. Harmon finished the war as a corps commander.

Following the war, he organized the military constabulary force in Germany and then served as deputy commander of Army Ground Forces before retiring in 1948.

Between the wars, Gen. Harmon graduated from the Army War College and the Command and General Staff School and was a West Point instructor. He served on the War Department General Staff for four years before going to Fort Knox, Ky., in 1939, where he helped organize the first U.S. Armored Force.

After retiring from active duty, he returned to New England -- he was a native of Lowell, Mass. -- and was president of Norwich University in Northfield, Vt., for 15 years before retiring a second time in 1965.

He is survived by his wife of 62 years, the former Leona Tuxbury, of the home in Hanover, N.H.: three sons, Halsey W., of Reedville, Va., Robert S., of Bethesda, and Ernest N. Jr., of Fullerton, Calif.; two daughters, Barbara Roll of Brantham, N.H., and Jeanne Oliver of St. Louis; a sister, Etta Betterley of Holden, Mass.; 17 grandchildren, and four great-grandchildren.