The flatirons back of Boulder, Colorado are huge blocks of sandstone that were uplifted millions of years ago when the present Rocky Mountains were forming. They are so-named because a front-on view suggests the stove-heated flat irons of long ago. I have heard that the same sandstone beds are 15,000 to 20,000 feet underground just 20 miles east of here. I measured the slope of the Third on this photo as 37 degrees. This is usually a technical rock climb. What do you do when you get to the top? - repel off the back side. Unfortunately, there have been a few fatalities on the Third Flatiron. It is now off limits to climbers from late fall to July, because of nearby nesting raptors.
Harold

