http://www.history.nd.gov/hp/PDFinfo/2_Cannonball_River_Study_Unit.pdf

the above study indicated 296 archeological sites and 334 archeological site leads just within the Cannonball River Study Unit

http://www.psc.nd.gov/database/documents/14-0842/001-080.pdf

Energy Transfer's own materials (above) talk about how pre-historic materials will be handled in the event of unanticipated discovery.

by the way all those thousands of reference materials are available below:

http://www.daplpipelinefacts.com/resources/project-filings.html

because the US Army Corps has already agreed to withhold portions of the permit due to new information as indicated in the article is noteworthy.  the USACE is one of the most dismissive federal agencies there are they will discard any information that impedes development.  The USACE needs to be cleaned from top to bottom.

I found these facts in about 5 minutes of looking online smarter folks than I are refuting the claims made by DAPL