Archaeologists working on the proposed Obama Presidential Center site have uncovered artifacts from the 1893 World’s Fair, but according to state officials, they are not important enough to merit an addition to the National Register of Historic Places.

Jackson Park is already on the Register as the site of the 1893 World’s Fair, which is also notable for its association with the Fair’s head architect, Frederick Olmsted.

Using visual detection, coring, hand excavation, the surveyers found thousands of artifacts relating to the 1893 worlds fair, but concluded that none of the artifacts provided new information, which is required to justify adding them to the national register.

— Emeline Posner (@emelpos) March 29, 2018

The discoveries are part of a federal land survey in preparation for the construction of the Obama Center, expected to open in 2021. Most of the artifacts are small, white fragments of building material, but the artifacts also include animal bones, shards of building material thought to be from Louis Sullivan’s Transportation Building, and miscellanea left behind by the Fair’s 27 million visitors.

In order to be added to the National Register of Historic Places, a candidate must be associated with important historical events or people, represent distinguishing features of a particular era of architecture or builder, or provide important historical information.

Although the artifacts are related to Frederick Olmsted, the landscape architect of the World’s Fair, as well as the Fair itself, they do not provide significant new information about Jackson Park. Therefore, the artifacts are not eligible to be added to the National Register of Historic Places.

Had the site been added to the Register, construction on the Obama Center could have been stalled or threatened. The City of Chicago is still reviewing the Center’s construction plan, the timeline of which has not changed.

In wake of the artifacts’ discovery, the University is hosting a meeting on Thursday to discuss the findings.