 Ashfall Fossil Beds, a Museum locality
originally named Poison Ivy Quarry, was discovered in 1971 by paleontologist Mike
Voorhies. A scientific excavation was carried out between 1977 and 1979. Over these three
field seasons, nearly 100 complete rhinos (of the genus Teleoceros) were discovered
and collected, along with dozens of horses, camels, turtles, cranes, and other animals. In
the mid 1980's, Mike (shown at left working on the skull of a rhino) and his crew returned
to the site to continue explorations and assist with the preliminary plans for a new state
park. Our intent this time was not to collect the fossils, but to expose them and
leave them in place in the volcanic ash for people to see! |
 The state of preservation of the skeletons
at Ashfall is astounding and provides us with a detailed glimpse of Nebraska 10 million
years ago. Aspects of population dynamics, diet, disease processes, and even social
behavior are also preserved here as they are at no other known site. At right, preparator
Greg Brown does the detailed preparation of a probable mother-baby pair of rhinos (named
"Sandy" and "Justin" by the crew) in the Park's Rhino Barn.
Preserved in their death positions and touching noses, it is easy to sense the agony they
must have felt in their last moments of life. Several other similar associations, many
with young rhinos actually in nursing position along side adult females, were excavated
from the site in the late 1970's. |
 Preparator Ellen Stepleton works on the
skeleton of an adult female rhino named "Amy". Remarkably, this rhino still
carries within it's pelvic cavity the bones of her unborn calf. A closer look also shows
that her shoulder has been scavenged by some opportunistic carnivore, and her stomach and
mouth contain the remains of her last meal: grass seeds and leaves. Amy is
one of more than 25 skeletons (permanent residents!) so far exposed and visible in the Rhino
Barn. |
 Two of Ashfall's 1979 celebrities,
complete adult rhinos "Morris" (foreground) and "McGrew" (Background).
"Morris" (a male with large tusks and big feet!) and "McGrew" (a
female with small tusks and unborn calf) confirm the previously-suspected differences
between males and females of this species. Complete skeletons of mammals are rare in the
fossil record and add tremendously to our understanding of an animal's anatomy.
Catastrophic events that preserve populations or communities of animals are incredibly
rare and give paleontologists the equally rare opportunity to do highly detailed studies
of such things as population dynamics, sexual dimorphism, variation and behavior. |
 Within this "Barn" view are the
rhinos "Amy" and "Dr. Marie", a small three-toed horse (Pseudhipparion),
a small deer-like animal (Longirostromeryx), a camel, and numerous scattered bones.
"Dr. Marie" was named after the person who first described the abnormal bone
growth associated with severe lung damage or disease. This condition is occasionally found
in living animals and humans, but is seldom seen in fossils. Because it is present in
every animal found at Ashfall, however, it is likely that the lung damage was caused by
breathing large quantities of volcanic ash. |
 An aerial view of a portion of the Ashfall
site. This photo was taken during the Park's development and shows a series of 6-meter
sampling grids layed out on the newly-exposed surface of the ash bed. The overburden (sand
and sandstone) and the upper 3 to 5 feet of volcanic ash have been removed, leaving the
fossils safely buried under another 5 feet of ash. The Rhino Barn (not yet built
when this photo was taken) now covers the area at the bottom of the picture. Exploration
has indicated that this is a very small portion of the actual bone-bed. Much work remains
to be done here, and many more exciting discoveries will be made in the future, perhaps
even while you are watching! For detailed information about Park visitation hours and location, visit the Nebraska Game and Parks Commission Ashfall Page. |