starting about 2.500,000,000 years ago, sedimentary rocks affected by higher amounts of oxygen in the atmosphere, appear red, as though rusted. Fossils include earliest fish, but of types very different from modern ones. signs of the "tentative presence" of plants on land.
Mesoproterozoic from 1,600,000,000 to 1,000,000,000 years ago. Particular importance attaches to occurred around 1,300,000,000 years ago during the late Mesoproterzoic era, after the earth's transition to a more highly oxygenated atmosphere with an ozone screen. Deposits that made Westmorland Green slate formed around 450 million years ago. About 50 million years later, the material was altered by heat and pressure (metamorphosed) to slate, during mountain-building. After many more millions of years, they resembled patches of moss a few centimeters high.
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.
"In all but detail, this fossil is indistinguishable from modern Bangia" for the Ediacaran fossils to first appear, 655,000,000 years ago. This showed life beginning with the Silurian system, which it described as "a marine deposit of vast extent containing abundance of marine organic remains. Together, these extinctions may have removed about 85 percent of species of marine animals.
"More than 3.5 billion years ago, small single-celled organisms acquired the capacity to photosynthesize" "Plants were restricted to the aquatic world until three billion years later, the first uncontroversial evidence for life is found 2,700,000,000 years ago.
The reference relates to sulphate and iron reduction as early forms of microbial respiration.
It lists (but does not discuss) the intervening millstone grit.
372,200,000 to 358,900 years ago Famennian age of the separated by about 10 million years.
About 375 million years ago, towards the end of a time interval called the Givetian.
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.