This Specimen has been sold.
11.4" Slab of Dendrites On Limestone - Utah
This is a 11.4" slab of section of limestone with manganese dendrites on the surface. While they look like plant fossils they are mineral formations, that often occur between layers of sedimentary rock. They are quite attractive to look at though.
Dendrites that occur within rock are most often a result of intruding (percolating) mineral solutions that contained manganese and/or iron. These solutions can work their way through microscopic cracks in the rock, leaving behind a branching pattern throughout the rock. By an untrained eye, these can be mistaken for plant fossils within the rock.