"Boyle Chert, or Boyles. Source is in the Inner Bluegrass area of Kentucky, centered in Boyle, Lincoln and Garrard counties, with an outcrop in Powell Co. Cortex is often white and chalky. Variable colors can be blues, yellows, tans. Waxy to earthy texture, can be translucent in some rare cases. Seems to have a decent amount of fossils present. Some high quality pieces are translucent and can mimic Flint Ridge."
photos courtesy of Kyflintguy