The reference relates to Multicellular filaments from arctic Canada identified as a red algae Bangiomorpha pubescens. The curtain rises on a drama in the sea that has already begun, and has been going on for some time". London, Published by James Reynolds 174 Strand, 20t.10.1849. The first of these began about 443 million years ago.
Three strata of toadstone had been found, and the limestone under the third was as far as miners had reached. The map project describes the "shallow tropical sea surrounded by coral reefs" in which the limestones were laid down and how "subterranean volcanoes erupted spasmodically through the sea floor, covering the limestones with ash and lava" which formed the toadstone.
is Galena (lead sulfide) formed as pockets or veins in carbonate rock into which the mineral bearing fluid rock has intruded.
Galena can contain minor amounts of antimony, arsenic, bismuth, cadmium, copper, silver, and zinc See and stalagmites.
Encountering impermeable strata (such as toadstone) it forms underground lakes in the limestone which overflow to the surface as natural springs (a resurgence).
All of the major animal groups of the Ordovician oceans survived, including trilobites, "When I view all beings not as special creations, but as the lineal descendants of some few beings which lived long before the first bed of the Silurian system was deposited, they seem to me to become ennobled.
Judging from the past we may safely infer that not one living species will transmit its unaltered likeness to distant futurity." (Charles Darwin) From primal swamp to speaking humans: Ernst Haeckel said (1903) that the Pithecoiden (monkey) theory of human evolution requires tracing our animal ancestors before monkeys.The end-Frasnian extinction was most pronounced in tropical environments, particularly in the reefs of the shallow seas.Reef building sponges called stromatoporoids and corals suffered losses and stromatoporoids finally disappeared in the third extinction near the end of the Devonian.4,540,000,000 (4.54 billion) years ago Formation of planet Earth - Usher's date was ).Archeozoic: end of Azoic to 2,500,000,000 years ago: The era of the earliest living beings on earth.This was not adopted, but his division into Mississippian, for the 's "Story of a piece of coal" focuses on coal formation, but includes a section on the carboniferous limestone.