<a href="https://en.wikipedia.org/wiki/Cretaceous%E2%80%93Paleogene_boundary" class="extiw" title="en:Cretaceous–Paleogene boundary">Cretaceous–Paleogene boundary</a> at Raven Ridge in NW Colorado
<p>Astronaut photograph ISS018-E-11127 was acquired on December 6, 2008, with a Nikon D2Xs digital camera fitted with an 800 mm lens, and is provided by the ISS Crew Earth Observations experiment and Image Science &amp; Analysis Laboratory, Johnson Space Center.
</p><p>It should be noted that the K-T boundary here is represented by an erosional unconformity along Raven Ridge and rocks immediately below, above and containing the K-T boundary are not present.
</p>
USGS Geologic Quadrangle Map, Banty Point Quadrangle, Colorado GQ-703.
NASA
<a rel="nofollow" class="external free" href="http://earthobservatory.nasa.gov/IOTD/view.php?id=36504">http://earthobservatory.nasa.gov/IOTD/view.php?id=36504</a>