The geological periods of the Paleozoic to Cenozoic eras: Precambrian, Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian, Triassic, Jurassic, Cretaceous: Pregnant Camels Ordinarily Sit Down Carefully, Perhaps Their Joints Creak

Stalactites hang from the ceiling, stalagmites rise from the floor of a cave. The 'mites go up and the 'tites come down. When one has ants in one's pants, the mites go up and the tights come down. (Note: In a strict scientific sense, a mite is not an ant, although "mite" in common speech can refer to any small creature.) Stalactites hang tight, hang down like tights on a line; stalagmites might bite (if you sit on them), might reach the roof.