Page 43 - visitorGuide

■ Natural Cast of Dinosaur Track
Behind the migmatite is the natural cast of a dinosaur’s hind footprint that
filled with sand. The sand-filled track and the layers below and above it were
buried, compressed, and cemented to form rock. Later, they were uplifted and
eroded enough to be exposed at the surface. The sand-filled track has been
preserved, but the softer underlying layers that originally held the footprint
have been worn away.The sandstone cast now provides an upside-down look
at the ancient footprint.
Donated by H. Richard Blank, Jr., and Nancy A Blank Kaesler in memory of their father, Horace R. Blank, Sr., who col-
lected the fossil in the late 1930s.

■ Cast of Dinosaur Skull
While the origins of this skull cast are unknown,
it is nonetheless a perfectly fitting unofficial doorman
that greets GSA employees as they arrive in the morning and
then bids them farewell as they leave each evening.
■ Giant Selenite Crystal
Enormous, nearly flawless selenite crystals like this one are rare. Taking its
name from the Greek selenites (“moonstone”), this crystal was found in 1892
at the basal Entrada Formation at Caineville, Utah. Selenite is a transparent
variety of gypsum and is usually found with salts deposited along the edges
of hypersaline shallow seas in arid climates. It is especially common in rock
of Permian,Triassic, and early Jurassic ages across the Colorado Plateau.The
snow-white dunes at White Sands National Monument in New Mexico are
made of white gypsum sand.
Gift from the Department of Geology, Brigham Young University, Provo, Utah, through Morris S. Peterson.

Taking the stairs up to the right will lead you to the second floor (exhibits listed on
p. 37–42). The stairs going down lead to headquarters offices.

33FIRST FLOOR EXHIBITS