Pseudofossils are not fossils at all. They are inorganic oddities that can resemble fossils. Five examples of pseudofossils are illustrated below:
|top view of a concretion, 6 cm diameter|
|side view of the same concretion|
concretion = hard, compact, rounded mass of mineral matter and silt or sand grains. The concretion generally forms by localized precipitation from aqueous solutions commonly around a nucleus consisting of some debris, including organic matter (like a leaf, shell, or bone, etc.) in the pores of a sedimentary or fragmental volcanic rock. The concretion weathers out differently than the surrounding rock because the concretion is commonly more tightly cemented. Although it is possible that a concretion might have a fossil at its center, there is no easy way to determine this unless you crack open the concretion.
|dendrites, 15 cm in length|
dendrites = a chemical stain consisting of an oxide of manganese that crystallized in a branching pattern resembling that of certain plants. Upon close scrutiny, one will see that the dendrites pattern is not seamlessly connected (i.e., unlike plants).
|cone-in-cone from Pennsylvanian-age rocks in southern Oklahoma; entire rock 10 cm in width|
|cross section of a septarian nodule from Utah; slab is 16 cm in height|
|half of a geode, 15 cm diameter|