This image shows lava crumpled against the upstream side of an impact crater. In places where we see smaller ridges in the lava, they have steep faces that retain less dust and look rocky. Because of the lesser amount of dust, we might be able to see better details of the topography.
The crater itself is extremely old, having long been filled in with dust and its rim severely eroded. Note also the flat surrounding terrain.
Written by: HIRISE Science Team (audio by Tre Gibbs) (21 August 2013)
This is a stereo pair with ESP_019170_1860 .
More info and image formats at http://hirise.lpl.arizona.edu/ESP_018537_1860
Image: NASA/JPL/University of Arizona