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enjoy watching bank swallows in Red Wing, MN

There are four rock formations in Barn Bluff. This class focuses on learning how to recognize these four rocks. Meetings are on four Tuesdays, beginning February 8, 2005 and ending March 1, 2005. Classes take place at Twin Bluff School, between 4:30 pm and 5:30 pm. As a matter of strict policy, no student will visit Barn Bluff in the period from February 1, 2005 through March 31, 2005. At other times, all signs posted concerning Barn Bluff trail access will be observed.

The set of four classes is being coordinated by Joyce Peterson. Joyce teaches at Burnside Elementary School. Students in 4th and 5th grades are being invited to attend.

The rock formations making up Barn Bluff are: Franconia greensand, St. Lawrence siltstone, Jordan sandstone, and Oneota dolomite.

On Barn Bluff, the Oneota dolostone is covered with a layer of glacial till, and the till is capped with wind blown silt, called loess. There is a meadow near our home where dolostone has been quarried.

The above image was obtained at 10X. The specimen was collected on Feb. 18/05 at a swallow bank in the nearby meadow. The location is a hill with steep eastern face and gently sloping west side. The east face is bare loess with many swallow nest holes. Prairie grass covers the slope.

At 200X, the loess is seen to consist mainly of clear, rounded, silica silt grains. Each student places a pinch of loess in the palm of one hand, faces away from anyone who might be affected, then blows gently across the palm. The silt flies away much in the way it behaved when the silt bank was being formed.

  • Go to Google and search "Minnesota till loess". I find this reference, written by Terry Cooper, to be very interesting: Parent Materials for Soil Formation.

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