Well, I did keep digging and found a 2 inch P-trap with a 1 1/2 inch straight pipe attached via an adapter. I dug out all of the sand around it so I would have room to work.I also drilled and made an access through the slab at the center of the shower stall. I then cut off the trap at the point where it connected to a 2 inch straight pipe. I solvent welded a 2 inch sanitary 90 degree ell and brought a straight section of pipe to the center of the shower slab. At that point I connected a 2 inch P-trap and then a vertical 2 inch sched. 40 pipe to 1/2 inch above the slab. The pipe was plumbedand then was plugged with a rag until I finish the blocking and framing. I packed the sand back in the whole up to the slab and compacted it firm with a 2x4.
I feel better now that I found the P-trap and moved it's location to right below the 2 inch Oatey drain. Thanks again gentlemen. I have worked in emergency medicine for over 40 years, so if I can return the favor please e-mail me directly for any questions or advice.