Frank, that round thing in the top of the picture, any ideas..I've got several of 'em but this is the biggest, put a magnet to it but no iron, and a buddy of mine found out you can bust 'em with a hammer(what are friends for). They were found on flat terrain near old dried up creek beds...Rob
Those are most likely nodules. They appear to be sandstone from the picture. you can see the ancient bedding planes in them. They form when you have two different types of sediment and densities are present. Usually there will be some degree of differential compaction that allows the spherical shape to form. Many people mistake them for fossils. They are called psuedo-fossils. Typically it is called ball and pillowing. On the other hand, chemical and mineralogical differences can have the some result.( such as cryptocrystalline amorphous silicas) There is much discretion between nodules and concretions.
The top photo, could that be similar to what I posted sometime back? the exterior looks similar, but mine is spit in half with a symetrical hole in it. Pam emailed me said it could be a concretion or something to that effect. Can I Post it here to compare it?
Those rust colored items in question can have many variations depending on what millions of years have exacted on it, round elongated, el shaped, "globular etc. 99% will have barely dicernable tiny "bumps all over.
Just by coincidence on this topic, Check back with ML190's current input of WEST TEXAS INSITU.....That looks very much like the fabled rust devil right there next to the Pandora ! ! ! !