Embedded Files
🚙 Located 1.2 miles up the canyon from the intersection of Colorado Bvd. and US 14A at Spearfish Â
GPS Coordinates N44.28.044   W103.15.072     3,762 ft.
Site Access
       Directly behind the information kiosk located at the parking turnout along the right side of the highway is a short trail leading to the rocky riverbed of Spearfish Creek. Follow this trail to the riverbed and then look down the channel toward your right (northeast). Approximately 100 yards downstream is a tilted rocky outcrop (rock layer) exposed along the north side of the stream bed. As you walk toward the outcrop it will be on your left. Except during the spring melt or periods of exceptional rainfall, the riverbed is dry and relatively safe to walk. If you’re comfortable walking the riverbed, make your way down to the outcrop.
Echoes of Coastal Desert Update 3.pdfIn–Depth Geology Lesson pdf
A great document to print for those who want to dig deeper into the geologic story.Â
An ancient desert by the seaÂ
Where sands drift freely by.
Then turn to stone in layered styleÂ
Beneath the clear blue sky.
Field Exploration
Field Exploration
Are you ready for a trip back in time? During this exploration we'll take you on a short hike down the rocky Spearfish creek-bed to the ancient shoreline of a warm, salty sea – one that occupied this region of the continent eons ago. You won't get wet but you will be inspired!
This pdf Lesson Guide contains the specific directions for reaching our featured site as well as a detailed explanation of its geologic story for those desiring more depth. Mileage and coordinates are provided in each document and roadmaps and other learning aids can be found at the Geologic Resources link in the sidebar menu. The document is most useful if you have it in hand at the geologic site. Exercise extreme caution at the lesson site and along roadways.
Are you ready. . . . Let's Go!                        S. V. Fogarty  &  W. R. Stevens
The trail to the lesson site begins just to the right of the kiosk and leads to Spearfish Creek.
The trail to the lesson site begins just to the right of the kiosk and leads to Spearfish Creek.
Once you've reached Spearfish Creek, follow the stream bed to your right (NE) for about 100 yards.
Once you've reached Spearfish Creek, follow the stream bed to your right (NE) for about 100 yards.
DO NOT attempt to access this site when it's raining or during the spring melt. As you can see from the size of the riverbed cobbles the stream flow can be quite high during such events.
Sitting atop the Pahasapa Limestone, the Minnelusa Formation is one of the thicker rock units in the canyon. Age and thickness are approximates.
This lesson features the Minnelusa Sandstone which is exposed along north side of stream bed. The Minnelusa Formation was deposited during Pennsylvanian and Permian Time some 300 to 250 million years ago. Because this is a marine deposit we know that at the time of its deposition the Black Hill's, as an uplifted mountain range, did not exist. Note the thickness and position of the Minnelusa Formation in the stratigraphic column to the left.Â
This lesson features the Minnelusa Sandstone which is exposed along north side of stream bed. The Minnelusa Formation was deposited during Pennsylvanian and Permian Time some 300 to 250 million years ago. Because this is a marine deposit we know that at the time of its deposition the Black Hill's, as an uplifted mountain range, did not exist. Note the thickness and position of the Minnelusa Formation in the stratigraphic column to the left.Â
Sandy sediments, when deposited in the ocean, generally accumulate layer-by-layer close to the shoreline. In this outcrop we can clearly see those thin stratifications of sand which over the eons eventually lithified (hardened) into sandstone.
Sandy sediments, when deposited in the ocean, generally accumulate layer-by-layer close to the shoreline. In this outcrop we can clearly see those thin stratifications of sand which over the eons eventually lithified (hardened) into sandstone.
There's more to this story than meets the eye. Download our In-Depth Lesson pdf above if you desire a more thorough coverage.Â
Send comments to: partial.melting@gmail.com
Page updated
Google Sites
Report abuse