Steven Dutch, Professor Emeritus, Natural and Applied Sciences, Universityof Wisconsin - Green Bay
|Bear Butte is one of numerous small laccoliths in the northern Black hills. It is also a sacred site to the Lakota.|
|Left and below: Views from sd34. The white-capped ridge on the right is not igneous rock at all but an upturned collar of Paha Sapa (Madison) Limestone.|
|Left and below: Views from sd79|
|Left and below: The rocks of the laccolith are as utterly monotonous as possible.|
|Left: the only variety in the rocks is provided by occasional zones of slightly darker and more vitreous rock.|
In the sketch map above the summit trail is shown approximately in purple.
Once over the eastern spur and through the saddle, there is a wonderful view of the high plains to the north and east. The long and very straight stream is Spring Creek.
|Looking down onto the upturned collar of Paha Sapa Limestone on the northeast side of Bear Butte|
|Looking back along the trail to the saddle and the eastern spur.|
|The eastern spur with the ridge of Paha Sapa Limestone beyond it.|
|Switchbacks just below the summit looking south along sd79.|
|Last switchback before the summit.|
|It doesn't seem fair that after huffing and puffing up 800 vertical feet, you should be able to look down and see your car.|
Panorama looking southeast showing the upturned Paha Sapa ridge in the left middle distance.
Looking south and southwest. Bear Butte Lake is at right and sd79 in the center. Harney Peak is just barely visible above the far end of the road. It barely peeks over the intervening hills.
This panorama actually spans more than 360 degrees, starting in the east looking along the summit ridge. However, different summit features appear at each end because the panorama uses frames taken from different vantage points.
Bear Butte is a laccolith with a well defined upturned collar of Paleozoic rocks. The best exposed part of the collar is shown in blue. West of Bera Butte is a lower dome, possibly a laccolith that has not been exposed yet by erosion. The dome is visible on the surface as a series of cuestas (green). The cuestas are topographically obvious but lack good accessible outcrops. The best place to see the dip of the layers is where sd79 crosses the innermost cuesta. The road to the east just south of the stream affords the best views of the upturned collar on the northwest side of Bear Butte.
|Left and below: views of the outer cuesta from the road just north of the reservoir.|
|Left and below: Views of Bear Butte from the northwest. The wooded hills at the base are the upturned collar of Paleozoic rocks around the laccolith.|
|Left: North-dipping cuesta of Minnelusa Formation along sd79. This is the most easily visible outcrop illustrating the structure of the western dome.|
|Left: The arcuate cuestas of the western dome are visible beyond
the road (sd79). The Black hillsare in the distance.
Below: Additional views of the cuestas. Note the distinctive red of the Spearfish Formation below (east of) the road left of center.
|Views from 30,000 feet late in the afternoon. The peak is prominent and Bear Butte Lake is rimmed in white. The cuestas of the western dome stand out in shaded relief.|
Created 09 August 2004, Last Update 06 June 2020