Ferns, lycopodiaceae, Equisetaceae, Sigillariae, Stigmariae, Coniferae.
"The Student's Elements of Geology"
Sir Charles Lyell
307 und 314. Where many beds of coal are superposed over one another, the families and species are not always blended, being most frequently grouped together in separate genera; lycopodiaceae and certain ferns being alone found in one bed, and Stigmariae and Sigillariae in another.
"COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1"
Alexander von Humboldt