#1Glassy volcanic rock shot through with white calcite veins and xenoliths (foreign rocks) of olivine. This large black rock represents the Cretaceous volca-noes that were active at the time of the dinosaurs.

Sand-size grains of broken shells weredeposited as lime sand on a Cretaceousoffshore bar. A chemical reaction occurredsometime not long after depositioncemented it into the hard limestone.

#2

This microcave has a pale orange fillingand mini-stalactites and stalagmites. Thecalcite below it, probably also a cave fill,has beautiful white calcite crystals. Thelimestone was deposited during theCretaceous, at the time of the dinosaurs,but the caves formed much later.

#3

Water has dissolveda crack through theEdwards limestone.Sit here and thinkabout how fast itdissolves. The cavesare much youngerthan the dinosaurfootprints that are inthe rock. Imagine howlong ago dinosaurswere walking around!

#4

The Prince Sago, a large tree fern, was an important partof the Mesozoic landscape. This one was imported fromTaiwan . Do you think dinosaurs could have eaten them?

#5

Hartman Prehistoric Garden Geo Treasure Hunt

http://www.beg.utexas.edu/geowonders/dinosaur

Fossilized wood (also called petrifiedwood ) is ancient wood that has beenreplaced by minerals, mostly fine-grainedquartz. Plant fossils like these help usreconstruct the ecosystems of dinosaurs.

#6

The magnolia is aflowering plant thatwas newly evolved atthe time of thedinosaurs. This oneis called a bananamagnolia because ofthe fragrance of itsflowers in spring.

Insects were animportant part of theMesozoic landscape;they predate theprehistoric garden.

#8

Limestone is a rock created mostly by livingthings. These high-spired snails (gastropods)grazed on algae and are common neartrackways.

Trackways of a three-toed dinosaur arecopies made in slightly harder limestone

than the originals. If you look closelyyou can see the saw and chisel marks,which tell you that they are copies. How

many can you find in the garden?

#9

#10

#7

Hartman Prehistoric Garden Geo Treasure Hunt

http://www.beg.utexas.edu/geowonders/dinosaur

Horsetails are ancient plants that evolvedeven before the dinosaurs, during theCarboniferous Period.

#13

This force of nature is important in exposingtrackways at the surface and adds to anygarden.

#12

Replica of a fossil turtle shell found duringthe excavation of dinosaur tracks. Theturtle was part of the dinosaur ecosystem.The display at the Texas MemorialMuseum shows how fossil fragments of aturtle were reconstructed.

#14

Chert nodule in limestone. This hard rock,also called flint , is formed of microcrystallinerock that was used by Native Americans tomake arrowheads.

#11

Hartman Prehistoric Garden Geo Treasure Hunt

http://www.beg.utexas.edu/geowonders/dinosaur