Butte, Montana Airport Is in a Wide Flat Dry Valley.
“ cross the Continental Divide, then go down into a valley. …“

Near airport, several miles East & South of Butte, MT. Although the ZMM Route necessarily goes through Butte, MT, it is not mentioned by the narrator.
….The narrator often avoids mentioning big, noisy, congested “no quality cities”, which he doesn’t like. …. This lack of mention also seems to hold for anything else along the ZMM Route that he (or Author Robert Pirsig) happens to dislike!
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…. Satellite View Of Butte, MT, Showing Deep, Huge, Mining Pit (Black area at Red Pinpoint Viewing Stand.) RIGHT Click & Select New Tab => AFTER this satellite view comes up, notice that the mining pit & waste dumps are as BIG as Butte, MT => ..
..A) Whitish-Yellow Mine Dumps, North of Butte, MT, and
..B) Blue-Greenish “Yankee Doodle Tailing Pond”, also a Mine Dump.

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(Photo = 109-0962 + 109-0963sc ...... ZMM Page = 236 ...... WayPt = 240w 5601ft)