I assume this is under construction? You should put that up before this page is deleted.
120 West, not East
-120 should start the longitude. Click on nearby mountains and rocks. It shows that this mountain is over 500 miles from Sierra Buttes. That can't be right.
Old version: 39.7084°N / 120.688°E
current version: 39.70840°N / 120.6881°W
topozone: 39.7084°N, 120.6881°W (NAD27)
The marker has always been right on the summit when the user clicks the "Topozone Map" link. What is not obvious is that when the user clicks the link, the Datum becomes set to NAD27 by Topozone; this apparently is the default Datum when no Datum argument is passed through CGI. If you hand enter these coordinates into Topozone, or another site, you must set the Datum to NAD27, otherwise the summit will be off by about ~300 ft; is this the difference you are seeing? It seems that Summitpost is to blame here as is not forcing the coordiantes to be NAD83/87 as is apparently the standard, but, I must have a link that works. What do you want me to do, have the NAD83 coords, and have the marker off target when the user clicks the link? That would look kludge.
If you think my cooridates are off by many miles, maybe you should refresh, because I had already made the E->W correction that you suggested. Click on the "Topozone Map" link on the Elwell page and see that the marker is right on the summit.
Take it easy,
You fixed it AFTER I left that comment