Penetration of the main strike of the range by a few deep glaciated valleys has created five (or six) main "clusters" of peaks; the easternmost around Dickson (including Penrose and Dk07, the range's second-highest peak), and just west of that a fairly heavily glaciated group around Scherle Peak. The third group has Tillworth as its highest summit, west of a noticeable pass separating it from the Scherle cluster. Ipoo, Tillicum and Marrow are perhaps part of the Tillworth group, but seem a somewhat separate cluster just west of another pass similar to that separating Tillworth from Scherle. North of the Ipoo group is a broad set of marshy/barren basins which lie up a side-valley of upper Slim Creek, with another cluster of peaks to the northwest of the Ipoo group. Just north of that cluster and across another basin-pass is the last and northwesternmost group of peaks in the Dickson Rangepass is the cluster containing Sorceror (the highest Dickson Range peak west of Tillworth) and Slim Mountain, and a host of subpeaks in that group around a group of small icefields. North of that group is the pass connecting upper Slim Creek to Nichols Creek; this pass is the limit of the Dickson Range.
In general, the clusters of peaks and connecting valleys west of Tillworth are much more "open country" than the eastern part of the range, which is fairly rugged, although it seems this area has not been extensively explored (except, no doubt, by prospectors). History: The eastern part of the Dickson Range was very likely explored by prospectors at the turn of the last century, although hunting parties are known to have roamed the range for decades before. Mt. Penrose, the cockscomb-like peak at the range's eastern end, above the Gun Lakes, acquired its name after being climbed by US Sen. Boles Penrose, who had hired famed hunting guide W.G. (Bill) Manson, himself a pupil of Hunter Jack. In the western portion most first ascents were done in the early 1980s by John Baldwin and Jean Heineman.