The Jordan Sandstone at "A" Street in McGregor by Robert McKay, Senior Research Geologist Geological Survey Bureau, Iowa,  Department of Natural Resources

From the grain terminal we’ll walk over to “A” Street and view an almost identical Jordan section to that at Point Ann North but one that is more readily accessible.  This section is now maintained as a small city park but is actually owned by the state.  A graphic representation of a measured section for the “A”Street Exposure is reproduced  on the right.  The lower portion of the section is composed of medium to large scale trough cross strata with minor to abundant intraclasts.  The sandstone is friable but stands well vertically because it is very weakly cemented by minute amounts of silt size dolomite rhombs. To read more about the "A" Street exposure of the Jordan sandstone click here.

Our next field trip stop will give us a look at a series of caves that were excavated into the Jordan Sandstone.  One of these caves lies just east of the "A" Street exposure.  The cave (photo left) housed the Elf House gift shop for a number of years.

 

Towards the western end of the exposure is the remains of an old brick lined cistern that was dug into the friable sandstone (photo below).

Stop 12 is next to McGregor City Well Number 6, back along Old Highway 18 about 2 blocks north