| Title | Comment | Keywords |
|---|---|---|
| Horizontal Rock Layers | 09:48 - 10:13 (00:25) / 0.5 MB | "James Sadd", "Principle of Original Horizontality", "original horizontality", horizontality, gravity, fold, deformation |
| Conclusion | 25:39 - 27:00 (01:21) / 1.5 MB | "James Sadd", radioisotope, "relative age dating", "absolute age dating", mineral, superposition, horizontality, "cross-cutting relationship", "radiometric age dating", geologist, "rock formation", "geologic structure" |