The Gangplank

The ramp the panel describes is why the Union Pacific crossed here: sediment laid unbroken against the granite gave the line a steady climb to Sherman Summit. Grenville Dodge later told of finding it in September 1865 while escaping a war party, telling his guide that if they saved their scalps they had found the railroad's pass. Historians have doubted the chase, since his diary records only Indian signs that day, and the engineer James Evans had already been surveying the range. The panel stood at an Interstate 80 pullout until 2005.

What the plaque says

The Gangplank The granite rocks to the west are more than a billion years old (Precambrian in age). The sedimentary rocks to the east are some 10 million years old (late Miocene in age). After the mountains were elevated, some 20,000 feet of rocks were eroded from their crest. Later the younger sedimentary rocks were deposited against the flank of the range. The time between the formation of the granite to the west and the deposition of the onlapping sediments to the east is measured in terms of more than ten hundred million years. You are now standing on the gangplank. Erected 1962 by Wyoming State Archives and Historical Department and Wyoming State Historical Society

Where it stands

Worth the stop nearby

• Vedauwoo — 14 mi
  Knobs of 1.4-billion-year-old granite between Laramie and Cheyenne, rough as sandpaper and famous among climbers for its wide cracks.
• Cheyenne Frontier Days — 15 mi
  A railroad agent's excursion scheme for a town with no crop to celebrate, which became a six-hour show in 1897 and the Daddy of 'em All.
• Wyoming State Capitol — 15 mi
  A sandstone capitol set to face the Union Pacific depot down one long street, its copper dome gilded in 1900 when the copper tarnished.

More markers nearby

• Tree Rock — 12 mi
• Tree in the Rock — 12 mi
• Lonetree on the Laramie Range — 12 mi
• Camp Carlin — 14 mi