Where on Earth? - July 2018

by The American Geosciences Institute
Tuesday, June 26, 2018

Click to enlarge photo

Clues for July 2018:

  1. At times of low runoff (as in this picture), the river drains through a solution cavity in Paleozoic limestone. During times of high runoff, however, water fills the dry channel above the cavity, spilling over the cliff and creating a 30-meter-high waterfall.

  2. The waterfall, located about 60 kilometers north of a colorfully named national park, was named after a nearby natural feature that collapsed in July 1988.

  3. This river is the better known of two in the state with the same “rocky” name, and is a popular destination for hiking, camping and fishing.

Name the waterfall & its host state.

Scroll down for the answer

Answer: At times of low runoff, Natural Bridge Falls in Montana, which lies about 60 kilometers north of Yellowstone National Park, drains through a solution cavity in Paleozoic limestone. At times of high runoff, the Boulder River flows over a cliff producing a 30-meter-high waterfall. Photo by Jim Sukup.

July 2018 Winners: Eric Asmussen (San Leandro, Calif.) Leslie Bright (Kingsport, Tenn.) R.J. Gauthier-Warinner (Interlochen, Mich.) Robert Kasper (Abingdon, Md.) Stephen Tomlin (Mount Evelyn, Victoria, Australia)

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