Oklahoma is known for its beautifully preserved Devonian and Ordovician trilobites.  Several uplift events in the region have exposed a wealth of Paleozoic fossils. The images and discussion here are from a March 2003 trip to the Arbuckle Mountains and Criner Hills of southern Oklahoma.  Formations of note are:

• Bois d'Arc Formation, Cravat Member; Lower Devonian; near Clarita, Coal County, Arbuckle Mtns
• Haragan Formation; Hunton Group; Lower Devonian; near Davis, Coal County, Arbuckle Mtns
• Bromide Formation, Pooleville Member; Ordovician; Carter County, Criner Hills.

A well-known location for collecting Devonian trilobites is called "White Mound", Haragan Fm., Hunton Group, near Sulphur, Oklahoma in Arbuckle Mtns.  This is a private ranch and a fee area owned by Pat and Merylyn Howe.  At the time of my visit, there was a $25 fee to visit, plus $5 per person. (See White Mound contact info below.)  At one time, it was a large mound (or hill) of white limestone.  But, this quarry has seen heavy activity by collectors so "White Mound" is somewhat of a misnomer.  It is more like "White Hole".  However, I was still able to find a few trilobites (not well-preserved) and many brachiopods.  In fact, the real story here is the brachiopods.  You can sit in one spot and easily collect 50 brachiopods within arm's reach.  They appear to be: Oxoplecia, Sphaerirhynchia lindenensis (Dunbar), Glyptorthis costellata (Cooper), and Hesperorthis sulcata (Cooper).  Other fossils of note are horn corals and crinoid stems.  I believe the trilobites I found are Huntonia oklahomae (Richardson) and Kainops invius (Campbell).

I also collected at various road cuts along I-35 and Hwy 77-D and visited Geological Enterprises, Inc. in Ardmore, OK to purchase some well-preserved Oklahoma specimens which I could not find myself.

Kainops invius (Campbell) Geological Enterprises, Inc.	Kainops invius (Campbell) Geological Enterprises, Inc.
Huntonia oklahomae (Richardson) Geological Enterprises, Inc.	Huntonia oklahomae (Richardson) Geological Enterprises, Inc.
Kainops invius (Campbell) my unprepped find	Kainops invius (Campbell) my unprepped find
Brachiopods: Oxoplecia, Sphaerirhynchia, Glyptorthis, Hesperorthis my finds

Also in the full set of images (see below) are images of the Woodford Shale (a Mississippian shale that is the source of most of Oklahoma's oil).

"White Mound"
Pat & Marilyn Howe
Rt. 1, Box 323
Sulphur, OK   73086
580-622-5366
howe926@brightok.net

For more on the geology of this area, see "Oklahoma Geology" (at University of Tulsa).  Also see "Devonian Trilobites of Oklahoma".