<Tr> <Th> Parent range </Th> <Td> Rocky Mountains </Td> </Tr> <Tr> <Th> Topo map </Th> <Td> USGS Yellowstone National Park </Td> </Tr> <Tr> <Th_colspan="2"> Geology </Th> </Tr> <Tr> <Th> Age of rock </Th> <Td> 2,100,000--70,000 years </Td> </Tr>

What's the biggest volcano in the united states