Sand, rocks, and mountains

how tall are the dunes in the middle?

Going back to the navcam stereo pairs at:
http://marsrovers.jpl.nasa.gov/gallery/all/spirit_n050.html
and comparing the dunes with the tracks left in the soil, it looks like the dune height might be about 1/3 the distance between Spirit's wheels, around a foot.

looks like hiroshima

are there mountains on mars or are they just volcanoes?