Today we rode the Mickelson Trail, a former railroad converted to a multiuse trail 109 miles long. The day started out sunny but cool and wound up cloudy and cold with a light rain. It was a nice ride anyway.

The Black Hills were formed by an uplift of hot magma rising under layers of sedimentary rock and shale. The center of the formation is the granite of Mount Rushmore surrounded by the slate shown above. Slate is formed when shale gets hot. Surrounding the slate is all the sedimentary rock I saw yesterday. On the right side of the photo you can see chunks of slate breaking away from the main rock.

Tomorrow is more of the Mickelson Trail as we ride past the Crazy Horse monument, through the town of Custer and on to Hot Springs. More chilly rain is forecast.