The nearby lava dome and tuya (subglacial volcano) Hogg Rock shows more similarity to the basaltic andesite deposits at North Sister, which are poorly enriched in incompatible elements. The part of the High Cascades that extends south from Mount Jefferson to Santiam Pass includes shield volcanoes, lava domes, and cinder cones.
The geological features near Hogg Rock, such as a lava dome and tuya (subglacial volcano), share similarities with the basaltic andesite deposits at North Sister. These deposits are not enriched in incompatible elements. The High Cascades region south of Mount Jefferson to Santiam Pass includes shield volcanoes, lava domes, and cinder cones.