Sixty-eight species of trilobites, 10 species of inarticulate brachiopods, two species of articulate brachiopods, one ostracode and fragments of sponges, pelmatozoan echinoderms and unidentifiable organisms constitute the faunas of the Riley formation. The fossils were collected from eight measured sections around the periphery of the outcrop area in Mason, Gillespie, Blanco, Burnet, Llano and SanSaba counties, Texas. All of the fossils are described and illustrated by stereophotographs. Two families, four genera and 16 species of trilobites, and three genera and five species of brachiopods are described as new.