I found the National Park one with the bison, need to get that one first.
Take a closer look at the NPS coins - all three of them have a bison as part of their design. It is the most obvious on the silver dollar, but the gold half eagle and CuNi clad 50-cent coin feature the National Park Service logo which depicts a bison.
Collecting history one coin or medal at a time! (c) commems. All rights reserved.