writes of fine-grained greenish sandstones deposited in freshwater in which land plant fossils are well preserved.

isotope carbon used dating things archaeology-52

All plants were responsible for the transformation, but Archaeopteris was important because it made up 90 percent of the forests during the last 15 million years when these changes accelerated" ...

"It was the first plant to produce an extensive root system, so had a profound impact on soil chemistry".

By carboniferous [carbon bearing] soils, Richard Kirwan in 1799 meant the "various sorts of earth or stone among or under which coal is usually found".

William Daniel Conybeare and William Phillips (1822, page vii) proposed to consider all rocks in an ascending order with a group including "not only the great coal-deposit itself, but those of the limestone and sandstone also on which it reposes" as the "medial" [middle] order.

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.

It lists (but does not discuss) the intervening millstone grit.

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.

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.

The end-Frasnian extinction (the largest) about 375 million years ago.