The ancient fossils are a record of when shallow seas covered much of the United States. While the fossils are of organisms that
are the precursors of many modern day organisms, changes in ocean geography and other factors eventually caused those older species to become __________.
-<span>- </span><span>It is considered to </span>be<span> the link between the lobe-finned fishes and early ... Climate and</span>geography<span> ... </span>Sea<span> levels were high with </span>much<span> of western North </span>America<span> under water. ... By the mid-Devonian, the </span>fossil record<span> shows evidence that there ... Plants, which had begun colonizing the land</span>during<span> the Silurian ...</span>