Limestone

The North River Stone School (Douglas No. 1, also called the Bennett School) was built in 1874 in place of the older log school on the plot. It is twenty-five feet by thirty-five feet and made of limestone from a quarry that was only half a mile south east from the site. A restoration effort began in 1962 and following its completion, the school was added to the National Register of Historic Places in 1977. As of 2024 it is maintained as a museum by the Madison County Historical Society on its original plot. It is open to the public upon request. 

The Stone Academy schoolhouse (Big Grove No. 1) was built circa 1842 – though there's no official record of its construction date – making it one of Iowa's oldest surviving schools. It was built using limestone from the McCune quarry that was about two miles northeast of the school. This material was rare for schoolhouses – especially in the mid 1800s when log buildings were more common – and is an indication of the community's wealth and commitment to education. The plot the building sits on was once a stagecoach route and trail for the military to travel between Dubuque and Iowa City.