iment ed ▁rock ▁in ▁a ▁stre ak ▁of ▁golden - red d ish ▁t int . ▁Ch unks ▁of ▁broken ▁rock ▁pill ars , ▁the ▁de br is ▁from ▁down s lo pe ▁falls , ▁salt ▁the ▁ground . ▁ ▁Ge omorph ology ▁E agle ▁Rock ▁particip ates ▁in ▁the ▁Austin ▁Bl uff s ▁area ' s ▁soil ▁type ▁of ▁the ▁" Tra v ess illa - R ock ▁out c rop ▁complex ," ▁as ▁mapped ▁at ▁the ▁scale ▁of ▁ 1 : 2 4 , 0 0 0 - ft ., ▁( ref . ▁US DA , ▁ 1 9 7 4 .) ▁To ▁understand ▁the ▁area ' s ▁soil ▁characteristics ▁in ▁more ▁detail , ▁we ▁may ▁consider ▁a ▁field - stud y ▁lecture ▁on ▁site ▁at ▁the ▁H eller ▁R anch , ▁where ▁Prof . ▁Thomas ▁P . ▁H uber ▁explained ▁the ▁ge omorph ological ▁orig ins ▁of ▁E agle ▁Rock . ▁The ▁E agle ▁Rock ▁cl iff ▁resulted ▁from ▁several ▁long ▁cycles ▁of ▁mountain - building ▁( ter med ▁" or ogen ies , ") ▁followed ▁by ▁er os ion . ▁He at ▁and ▁pressure ▁energ ies ▁that ▁had ▁thrust ▁up ▁the ▁mountains ▁produced ▁ igne ous ▁rock , ▁such ▁as ▁the ▁P ikes ▁Pe ak ▁p ink ▁gran ite , ▁which ▁eventually ▁de grad ed . ▁Natural ▁forces ▁dispers ed ▁and ▁depos ited ▁particles ▁of ▁the ▁rock ▁de br is . ▁Over ▁time , ▁the ▁sed iment ▁collected ▁and ▁cons olid ated ▁into ▁new ▁sand stone ▁at ▁the ▁Garden