Well, the turtle mystery is unsolved. We checked with the guy who we thought might have put the turtle in our yard, and he said he did not. And then, upon closer examination we noticed that the new turtle had a flat shell and webbed back feet...a water turtle. Looking even closer, we noticed a light red spot behind it's eye. This turtle is a Red Ear Slider...it not only likes the water but spends most of its time in the water. There are no creeks, ponds, etc. within a couple miles of us. We have no idea how this water turtle ended up in our back yard. Since it could not stay with our box turtles, we took a few more pictures (pictured here with Little George), measured it (8 inches long, about 6 inches wide) and looked for a place to let it go.
Amanda and I headed to a spot on Lake Arlington where we used to have a geocache. On the way down to the water, we saw several more Red Ear Sliders so we figured we picked a good place. Amanda took a picture of me with the turtle just before I set it down on the bank.
As soon as my hands came off the turtle, it dove into the water. If you look closely you can see it under the surface of the water (above and to the right of the shadow of my head) just before it disappeared into the muddy depths. We walked back up on the bridge and spotted it coming up for air and swimming around a couple times before we left.