After Arkansas Preservation redesigned their web site a few weeks ago, there are a number of issues with the NRHP part of the site.  I have found at least two instances of listings that are missing from search results, and numerous PDFs of listings are also missing.  If you find what seem to be missing entries, you can try to find them the NRIS mirror run by Elkman, which has all listings up to about April 2010 (i.e. it has no listings or delistings after then).  If they show up in Elkman but not on the Arkansas Preservation site, contact them (info@arkansaspreservation.com), they're pretty good about responding.  On the old web site, I would report errors or omissions that would be fixed within a business day.  Sometimes the omission from their site is caused by an imminent delisting.  For bridges, you can also see if Bridgehunter has images or other information (like better lat/lon, which these two listings need).

In this case, listings for "Cove Creek Bridge" and "Cove Creek Tributary Bridge" both show up in Elkman (Tributary=95000644, Creek=95000645), and are given separate resource identifiers (in the "Other Names" field in Elkman: Tributary=LO0051, Creek=LO0050).  Unfortunately, Logan County appears to be one of the counties whose nomination forms are not currently available on the web site, but they can send copies by email.  Bridgehunter has images of both bridges (look nearly identical), provided by the Arkansas Highway Dept. ''''♪piano