Nine new dolabrane-type diterpenoids, notoscarins A-I (<b>1</b>-<b>9</b>), including an unprecedented 6,18-cyclo-dolabrane-type diterpenoid (<b>1</b>) obtained through intramolecular cyclization, two rare 19-<i>nor</i>-2-chloro-dolabrane diterpenoids (<b>2</b> and <b>3</b>), six new related dolabrane-type diterpenoids (<b>4</b>-<b>9</b>), and one new butyrolactone derivative (<b>10</b>), were isolated from the Chinese liverwort <i>Notoscyphus lutescens</i>. The 6,18-cyclo-dolabrane and 19-<i>nor</i>-dolabrane carbon skeletons are reported for the first time. The structures of these compounds were determined on the basis of MS and NMR spectroscopic data, single-crystal X-ray diffraction, and electronic circular dichroism calculations. Preliminary bioassays showed that compounds <b>1</b>-<b>10</b> exhibited moderate to weak quinone reductase-inducing activity in Hepa-1c1c7 cells.