It is sufficient to say that these appear in all the rocks except the very oldest-the Caelenterata beginning, and the Molluscoids exhibiting an early order in brachiopoda, which seems to be dying out.
"Creation and Its Records"
B.H. Baden-Powell
This genus of brachiopoda was first found in Silurian strata, and is exclusively a palaeozoic form.
"The Student's Elements of Geology"
Sir Charles Lyell
The Aymestry Limestone contains many shells, especially brachiopoda, corals, trilobites, and other fossils, amounting on the whole to 74 species, all except three or four being common to the beds either above or below.
"The Student's Elements of Geology"
Sir Charles Lyell