Discovered on ebay:
Vintage Crochet Pattern for a Cowboy Hat
This is a crochet pattern from 1976 for a Cowboy Hat. Article says.... The unique cowboy shape is achieved by crocheting extremely tight even stitches. You work the hat in three parts: crown, band, and brim. Since the size of the band is flexible, decrease as necessary for a good fit. Be sure to stagger the places where you begin each yarn ( to prevent a seam from showing ) and slip stitch at the end of each round to keep the rounds the same height.....