Southeastward view across saddle between North and Middle Sisters. ...
In left foreground, ice-ravaged mafic edifice Little Brother is separated from North Sister by Little Ice Age trough of Collier Glacier. Both North Sister and Little Brother expose numerous oxidized scoria falls, whereas smooth black Middle Sister cone is cloaked by mafic lava flows. Brick-red ridge extending north (left) from North Sister is part of younger north-south vent alignment. Beyond South Sister cone (at upper right), which has several pocket glaciers, is smooth cone of Mount Bachelor behind it and rugged, barren Broken Top volcano to its left.
Hildreth et al., 2013