Close-up of terminal cliff of Talcu Glacier, coast of southeastern Alaska

Distant view of Taku Glacier, which discharges into Taku Inlet

Melt-water stream flowing from beneath Mendenhall Glacier, southeastern Alaska

U.S.S. Joseph E. Merrell moored at a low point in Ross Ice Shelf, Kainan Bay, Antarctica

Distant view of a segment of the Ross Ice Barrier, Antarctica

One of hundreds of Greenland glaciers—west coast near

Thule Navy helicopter passing a Greenland glacier en route to Thule

“Footprints in the sands of time” turned to stone Dinosaur seventy-five and one-half feet long

A Jurassic dinosaur 20 feet long

Pleistocene mammoth ten feet tall

Jupiter in blue light with satellite Ganymede

Saturn with rings most nearly broadside

Saturn in blue light, rings almost edge-on

Jupiter with shadow of satellite on disk, and both satellite and shadow

Two exposures of Jupiter taken 23 minutes apart

Sandstone slab from Agate Quarry, Nebraska, containing mass of rhinoceros bones

Elemental sulphur stored in vats each 1200 feet long, 180 feet wide, 50 feet high

Fossilized dinosaur tracks in Triassic sandstone, Navajo Canyon, Arizona

Dinosaur tracks in sedimentary rocks of hog-back west of Denver

Prehistoric animal tracks, Grand Canyon National Park

Grinnell and Gem Glaciers and Garden Wall, Glacier National Park, Montana

Grand Canyon of the Colorado River

“Granite Gorge” and Colorado River at bottom of Grand Canyon

Great White Throne, Zion Canyon, from Scouts Lookout

Grand Canyon from north rim Grand Canyon of the Colorado, showing horizontalism of rock strata

Successive seams of bituminous coal Brooks Comet