The last major round of volcanism, the Yakutsk Large Igneous Province, continued into the Carboniferous to produce extensive kimberlite deposits. This union of the paleo continents of Laurentia (comprising much of North America, Greenland, northwestern Ireland, Scotland, and the Chukotsk Peninsula of northeastern Russia) and Baltica (now most of northern Europe and Scandinavia) occurred near the beginning of the Devonian. [53] These tracheophytes were able to grow to large size on dry land because they had evolved the ability to biosynthesize lignin, which gave them physical rigidity and improved the effectiveness of their vascular system while giving them resistance to pathogens and herbivores. This period started about 419 million years ago and ended 358.9 million years ago. At the terminus of the Devonian, Earth rapidly cooled into an icehouse, marking the beginning of the Late Palaeozoic Ice Age. There was a significant increase in organic matter in the water bodies and on land during the Devonian. The second-largest continent, Laurussia, was northwest of Gondwana, and corresponds to much of modern-day North America and Europe. Cretaceous The extinction that occurred 65 million years ago wiped out some 50 percent of plants and animals. Trilobites continued their decline, while brachiopods became the most abundant marine organism. The newly evolved forests drew carbon out of the atmosphere, which were then buried into sediments. Heres how it works. [51] By the Middle Devonian, shrub-like forests of primitive plants existed: lycophytes, horsetails, ferns, and progymnosperms evolved. Overall most of the modern continental plates were grouped together on one hemisphere of the Earth. Deformed remnants of these mountains can still be found on Ellesmere Island and Svalbard. The Devonian Period is formally broken into Early, Middle and Late subdivisions. Devonian Time Span Date range: 419.2 million years ago to 358.9 million years ago Length: 60.3 million years (1.3% of geologic time) Geologic calendar: November 28 (6 PM)-December 3 (1 PM) (4 days, 19 hours) Devonian age fossil brachiopod, Death Valley National Park, California and Nevada. These tetrapods first evolved into land animals before the end of this Period. Trilobites (ToL: Trilobites Ba Lounge Heathrow Terminal 5 Opening Times, Articles W