[lemma=□] □
[lemma=the] □
[lemma=cliff] □
To the north - - on the craggy precipice - - a few paces from the verge - - up sprang the magnificent trunks of numerous hickories , black walnuts , and chestnuts , interspersed with occasional oak , and the strong lateral branches thrown out by the walnuts especially , spread far over the edge of the cliff . " I drove the car off the cliff . The archaeological elements include a rock shelter excavated by George Frison of the University of Wyoming , which uncovered 60 cultural levels spanning at least 11,000 years of occupation , along with extensive rock art on the cliff face . The cliff wall is festooned with life : white sponges as big as dinner plates and colonies of the bryozoan , Lophopodella carteri , a state listed species , cover the cliff face between the sponges . The cliffs are retreating from former positions far to the south . I remember being in total awe as I descended down through the cliffs of Coconino sandstone , petrified sand dunes , hundreds of feet deep . The ribbon of green that runs along the top of the cliffs from Colorado Avenue to just north of San Vicente Boulevard has flat walkways peopled by casual strollers , joggers , and the homeless . What about the cliffs ? Lack of archaeological evidence or toponyms suggesting earlier ruins or walls argues against defenses above the cliff . Moreover , if we follow for a few miles any line of rocky cliff , which is undergoing degradation , we find that it is only here and there , along a short length or round a promontory , that the cliffs are at the present time suffering .