Cordania falcata is a small trilobite and is uncommon in the Bois D'Arc formation. I found two examples that were prone and mostly complete, but neither were attached to matrix. Below is the better specimen of the two. It is about 95% complete and is missing a portion of the right genal spine. The trilobite itself is nearly oval shaped with a large rounded cephalon that typically has long genal spines that extend nearly the length of the thorax and pygidium. There is a small glabella with one furrow. The eyes are small, holochroal and slightly raised. The specimen below need to have some prep work done to expose the rest of the trilobite but should make for a nice example.
I found the specimen shown on this page in the Bois d'Arc formation (Cravatt member) near Clarita, OK which is Devonian in age (Lockhovian stage). The Bois d'Arc and Haragan formations interfinger with each other and are roughly the same age (Devonian, Lockhovian stage). They are both roughly correlative to the Helderberg fauna of New York and thus are contemporaneous with the Coyemans, Kalkberg and New Scotland formations.
Reference: "Trilobites of the Haragan, Bois D'Arc and Frisco Formations (Early Devonian) Arbuckle Mountains Region, Oklahoma" 1977 K.S.W. Campbell, Oklahoma Geological Survey, Bulletin 123, pg. 22, pl.5, fig 1-4