These images were taken within the July 26 - August 3 timeframe All images courtesy of NASA's Mars Pathfinder Project. Barnacle Bill, Yogi, Scooby Doo, and Lamb have been investigated by the Sojourner rover and its Alpha Proton X-Ray Spectrometer.
Couch is a large rock on the horizon.
The names are used by the Pathfinder team to help identify and keep track of the many rocks at the landing site. End of Day image taken by the IMP of Sojourner at Souffle. Here's Sojourner taking a ride over an obstacle. Piglet and Pooh Bear are just to the left and in front of the rover. This image from the IMP camera shows Mini Matterhorn in the foreground.