Nautilus

3 boulder problems · sandstone (Fountain Formation) · 5,875 ft

Take me there Routes ↓ Directions

Help locate these routes: survey the wall

How well located

Position on wall known 3

No route here has its own point yet. The map pin is the crag. At the wall? Survey it: 30 seconds per route.

The guidebook for this area

Colorado Bouldering: Front Range - Phillip Benningfield, Matt Samet - 2020 every crag it covers

From the publisher Bookshop.org

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The book has the topos, the descriptions and the local knowledge this page can't. Buying it helps support the people who know the crag best.

Rock, from the geologic map

Dakota Group (South Platte Formation, Lytle Formation). Mesozoic, about 145 to 100 million years old.

Consists of South Platte Formation and underlying Lytle Formation. South Platte Formation contains two or three yellowish-gray, well-sorted, cross-stratified, porous, fine- to medium-grained quartz sandstone sequences separated by dark-gray, silty, hard, locally carbonaceous shale, interbedded with thin quartz sandstone beds and gray to white refractory clay or porcellanite layers [see Bryant and others (1973) for more detailed description of members of South Platte Formation]. The South Platte is about 67 m thick. Lytle Formation consists of yellowish-gray, medium- to fine-grained sandstone and conglomerate; locally contains reddish iron stain. Well-rounded clasts in conglomerate composed of quartz, quartzite, chert, and some petrified wood; conglomerate generally near base of unit. The Lytle is about 24 m thick. In Fraser basin, combined thickness about 75 m (Taylor, 1975)

This is the map unit under this crag's map point, read from the 1:100,000 sheet (Kellogg and others, 2008, USGS Geologic Investigations Series 3000). The point can be a few hundred metres from the rock, a cliff often stands on the line between two units, and at that scale a line on the map is about 100 m wide on the ground, so the wall itself may be the neighbouring unit. The rock named at the top of this page comes from the public geology of this area; this card is the map's answer. Every crag on this unit: Dakota Group. Geology data: Macrostrat (CC BY 4.0), serving USGS and Colorado Geological Survey maps.

On the map since 1899

The USGS has mapped this ground since 1899. 25 historical sheets cover this crag's map point; the oldest is below.

Thumbnail of the 1899 USGS sheet covering Nautilus — **USGS 1:125000-scale Quadrangle for West Denver, CO 1899** · U.S. Geological Survey · 1899 · 1:125,000 sheet
USGS Historical Topographic Map Collection · Public domain · the record · placed by its coordinates

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Hidden as soon as you tell us, everywhere it appears, before anyone reviews it.

Public domain, U.S. Geological Survey. The sheet shows the ground as the survey found it then, which is why a trail or road you know may be missing. Every sheet over this point, 1899 to 1983: USGS topoView.

Photographs near this crag

Taken within 1.5 km of this crag's map point and published under a licence that lets us show them, from Wikimedia Commons. The coordinates say where the camera was, not what it was pointed at, so some of these will be the creek or the trail rather than the rock.

Denver Mountain Parks (Unsplash) · Natasha Miller tashography · 2015 · 1,249 m from the crag's map point
Wikimedia Commons · CC0 · the record · placed by its coordinates

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