The Late Devonian extinction event occurred around 375 to 360 million years ago.  During this mass extinction 19% of all families, 50% of all genera, and 70% of all species went extinct.  At this time, there were two major continents Euramerica and Gondwana that started to merge to create the supercontinent Pangea.  This extinction event is supposed to have lasted 20 million years and happened in pulses.   The cause of these pulses is unknown, but some theories have suggested changes in sea level caused by global cooling.  Most of the life that was destroyed during this mass extinction event was marine life even though land life had developed by this time period.

BBC Nature – Late Devonian mass extinction videos, news … http://www.bbc.co.uk Late Devonian mass extinction. Three quarters of all species on Earth died out in the Late Devonian mass extinction, though it may have been a series of …

Devonian Times – Mass Extinction http://www.devoniantimes.org Late Devonian Mass Extinctions One of the “Big Five” Scientists recognize a number of mass extinctions (extinction events that far exceed background extinction rates …