| A | B |
|---|
| uniformitarianism | current geologic processes are the same as those from the past |
| strata | rock layers |
| relative age | age of an object compared to another |
| bedding plane | boundary between 2 rock layers |
| law of superposition | older layers are below younger layers |
| unconformity | break in geologic record |
| principle of original horizontality | if undisturbed, sedimentary rock form horizontal layers |
| graded bedding | coarse or heavy particles are in the lowest layers |
