[Illustration: 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.
[Illustration: 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.]