Mark Trail started life as a newspaper comic strip created by cartoonist Ed Dodd. Introduced April 15, 1946, the strip centers on environmental and ecological themes. It was syndicated through the New York Post in 1946 to 45 newspapers. Dodd, working as a national parks guide, had long been interested in environmental issues. The character is loosely based on the life and career of Charles N. Elliott (November 29, 1906 - May 1, 2000), at the time a U.S. forest ranger who edited Outdoor Life magazine from 1956 to 1974. Dodd once said that the physical model for Trail was John Wayt, his former neighbor in north Atlanta.
On January 30, 1950, Mutual Broadcasting System launched a radio adaptation, Mark Trail, featuring Matt Crowley in the title role. The 30-minute episodes aired three times weekly, and 174 episodes were produced, running until June 8, 1951. A second radio series, starring Staats Cotsworth, was broadcast on ABC beginning September 18, 1950, with 51 half-hour shows that ran thrice weekly until January, 1952. The series then switched to a 15-minute format, producing 125 episodes that aired weekdays through June 27, 1952. Only a handful of the 15-minute episodes are known to have survived. (Source: wikipedia.org)