The Masked Raider was the first adventurer of the Old West published by Marvel Comics. He was Jim Gardley, a young cowpoke in 1830s Texas. He was originally approached with the offer to serve as hired muscle for a powerful rancher. When he found out the boss wanted him to "convince" all the small ranchers in the area to sell their lands to him at dirt cheap prices, Gardley turned down the offer. The rancher then framed him for cattle rustling and had him jailed.
Escaping, Gardley started preparing himself to take revenge. He created the costume identity of the Masked Raider, perfected his aim and draw and partnered himself with a feral white horse by the name of "Lightning". His costume consisted of a red shirt, black pants, brown boots, a white hat and a black mask.
The first pulp magazine published by Martin Goodman the eventual founder of Timely / Atlas / Marvel comics was The Masked Rider from Ranger Press in 1934. Which as of today is one of the rarest and hardest to find Pulp Magazines.
The first issue was a reworked novel by Oscar Schisgall called The Black Caballero which introduced the Masked Rider and his Indian companion Blue Hawk, while seeming a copy the Lone Ranger the Masked Rider was in large part more of a Western version of The Shadow.
The pulp was published regularly and written by a number of different authors so that between 1934 and 1940 when the character was sold to Standard Publication only 13 issues of the Martin Goodman version was published.
After the sell to Standard / Nedor Timely stopped printing stories about the comic book version of the Masked Rider in Marvel Mystery Comics.
Standard changed the character to a more conventional Western style hero and put the pulp on a more regular publishing schedule which ran until 1953, at the same time that they got the rights to the pulp character they also started publishing their comic book version of the Masked Rider.