Call of Cthulhu 7th Ed RPG: Down Darker Trails -Terrors of The Mythos in the Old West

Call of Cthulhu 7th Ed RPG: Down Darker Trails - Terrors of The Mythos in the Old West - Rules of Play says:

Down Darker Trails is a new setting for Call of Cthulhu—the American West of the late 19th century. The era of gold rushes, outlaws and lawmen, discovery and expansion.

Here you will find the means to create Old West investigators, new occupations, new pulp talents, and new skills. Captured in text and image is the history of the Old West, famous individuals, playing American Indian heroes, notable places and sites, as well as inspiration and guidance on bringing the terrors and mysteries of the Great Old Ones into your games.

Two complete towns, the gold-hungry Pawheton and San Rafael on the Texas border, are fully detailed, providing Keepers with ready-made inhabitants and locales from which to stage campaigns. Four different Lost Worlds are discussed, from the weird subterranean world of K’n-yan to the eerie Shadow Desert.