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.

Reef building sponges called stromatoporoids and corals suffered losses and stromatoporoids finally disappeared in the third extinction near the end of the Devonian.

It mentions the following periods to indicate how long ago coal was formed: Carboniferous followed by 359,200,000 - 326,400,000 years ago Dinantian series or epoch from the Lower Carboniferous system in Europe 326,400,000 to 313,400,000 years ago Namurian stage in the regional stratigraphy of northwest Europe are found - Silicious Grit, providing stone for building and millstones - Shale - then lime-stone and toadstone alternately.

The veins of metallic ores appeared in the limestone.

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

"Among the most attractive of these" tree-fern once called Cyelopteris (Round-leaved Fern), re named Palasopteris Hibernicus (Primitive Irish Fern). It was the "monarch of the primeval forests" whose "graceful fronds bent over the clear waters of a lake".

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