blue brown bushes sky snow trees white college colorado Denver school theater Tivoli university ammonite animal evolution fish fossil history live Mineral mineralization nature paleontology stone Shrimp horseshoe crab countryside ewe farm farming field flock grass grassland lamb livestock mammal ovine pasture sheep terrestrial animal vertebrate wildlife wool box box top brown wood copy space grain layer old old wood sign space texture wood texture aspen autumn change color colors Leadville leaf leaves atlantic Azores cruise hills ocean pastel sea