Cretaceous–Paleogene boundary at Raven Ridge in NW Colorado 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 & Analysis Laboratory, Johnson Space Center. 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. USGS Geologic Quadrangle Map, Banty Point Quadrangle, Colorado GQ-703.