http://en.wikipedia.org/wiki/Hoodoo_(geology)
Geology: The science that deals with the Earth's physical structure and substance, its history, and the processes that act on it.
Source For Definition: http://www.google.com/#hl=en&sugexp=les%3B&gs_rn=3&gs_ri=psy-ab&pq=geology%20def&cp=11&gs_id=1o&xhr=t&q=geology+definition&es_nrs=true&pf=p&safe=off&tbo=d&sclient=psy-ab&oq=geology+def&gs_l=&pbx=1&bav=on.2,or.r_gc.r_pw.r_qf.&bvm=bv.42553238,d.aWM&fp=aaf2fb22d1131062&biw=1440&bih=838