The phases and phase transitions of solid cycloheptane are examined with differential thermal analysis, with two new findings. Phase I samples cooled below similar to 200 K directly transform to phase III, not phase II as reported earlier. Phase III readily supercools through the III-IV transition, yielding a glassy crystal IIIg or transforming into a previously unknown metastable phase, III’, depending on details. These findings impact the identification of the phases studied in previous reports. Deuterium NMR of phase III shows that the reorientations are not isotropic, indicating that no molecules reside in sites of cubic symmetry. The deuterium spectrum suggests several inequivalent sites in phase III.