Friday, 11 August 2017
We blasted across South Dakota today at 80 mph on I-90. It makes for miserable gas mileage, but it really makes a difference when you’re driving 400 or 500 miles in a day.
We spent the night in Wind Cave National Park. Even though it’s quite close to Mt. Rushmore and other Black Hills attractions, the campground was far from full.
We toured Wind Cave, a “dry” cave known for unusual rock (calcite) formations.
We blasted across South Dakota today at 80 mph on I-90. It makes for miserable gas mileage, but it really makes a difference when you’re driving 400 or 500 miles in a day.
 |
| Eastern South Dakota -- agricultural and grazing land with gentle hills. |
 |
| South Dakota “badlands” toward the western end of the state. |
We toured Wind Cave, a “dry” cave known for unusual rock (calcite) formations.
 |
| The only natural entrance to Wind Cave is this small hole. Air pressure differences causes air to flow in and out of this entrance at speeds up to 70 mph (although it is usually less than that!). |
 |
| “Boxwork”, a calcite formation in Wind Cave. |
 |
| A closer look at boxwork. |
 |
| More boxwork. |
 |
| “Frostwork” and “popcorn” are the other calcite formations in Wind Cave. Since it’s a dry cave, there are no stalactites, stalagmites, or flowstone formations. |
No comments:
Post a Comment