Cecil Rowe Findley, 78, who worked for the National Geographic Society for 31 years before retiring in 1990 as an assistant editor, died of congestive heart failure April 9 at his home in Falls Church.

He came to Washington and joined the Geographic in 1959. He held a variety of writing and editing assignments that made use of his expertise in the history of the American West.

He covered 25,000 miles of the West for the Geographic's book "Great American Deserts." Over the years, he explored Death Valley, rode stage coaches and retraced the steps of 19th-century Western photographer William Henry Jackson. He also retraced Pony Express routes.

Over the years, his editing duties included serving as "issue editor" of the National Geographic magazine.

A Geographic spokesman said that the January 1981 issue of the magazine carried a piece he wrote on the historic and massive eruption of Mount St. Helens in 1980. National Geographic readers voted this article the most popular the magazine ever published.

Mr. Findley had been working on a story on national forests near the mountain when he found geologists were monitoring the volcano. Mr. Findley took Sunday, May 18, 1980, off to visit friends when the volcano erupted unexpectedly. He returned to the scene and wrote of the event and its aftermath.

He was a recipient of the Society's Distinguished Service Award.

Mr. Findley, a native of Willow Springs, Mo., was a 1943 journalism graduate of the University of Missouri. He served as an Army Air Forces bombardier in the Pacific during World War II and later retired from the Air Force Reserve as a lieutenant colonel.

Before coming to Washington, he worked for several Midwest newspapers, including the Kansas City Star.

Mr. Findley was a member of First Christian Church in Falls Church and sang in its choir.

Survivors include his wife, the former Virginia Holt, whom he married in 1950 and who lives in Falls Church; three sons, Stephen, of Reston, and David and John, both of Falls Church; and two grandchildren.