PSEUDOFOSSILS
Among the many inorganic objects formed by nature there are some that bear superficial resemblance to plants or animals. Because they are often mistaken for organic remains, these objects have been called pseudofossils, or “false fossils.”
Dendrites
Fig. 3. Dendrites. These thin branching mineral deposits bear a marked resemblance to plants, hence they are called pseudofossils.
Although these closely resemble the remains of ferns or other plant material ([fig. 3]), dendrites are actually thin incrustations of manganese dioxide. They are often found along the bedding planes of [Cretaceous] and [Paleozoic] (geologic time scale, [Pl. 1]) limestones in many parts of Texas.
Plate 4
Dinosaur tracks in limestone in bed of Paluxy Creek near Glen Rose, Somervell County, Texas.
Photograph courtesy of the American Museum of Natural History.
Permission to reproduce by R. T. Bird.
[Slickensides]
These are striations that are produced when [rock] surfaces move past each other while being fractured. [Slickensides] may superficially resemble certain of the [Pennsylvanian] coal plants of Texas.
Since [slickensides] are commonly at an angle to the bedding plane and plant remains lie parallel to the bedding plane, the two are usually easily distinguished.
Concretions
Many shales and sandstones contain hardened masses of minerals and [rock] that are often mistaken for fossils. These masses, called concretions, are usually found weathered out of the surrounding rock and may assume the shape of bones, flowers, vegetables, turtles, etc. Although these concretions do not represent organic remains, it is sometimes possible to find true fossils inside them.