The paleontologists who worked to recover fossils near Granger last week like to think small, but that’s a good thing for science.
A team led by James E. Martin, PhD, spent a day unearthing fossil bone fragments, some of which are so small as to be virtually invisible to the untrained eye.
Martin is the Executive Curator of Museum of Geology and Professor of Geology at South Dakota School of Mines and Technology in Rapid City.
He said the school’s paleontology program is one of the largest in the country.
The Granger dig was one of the stops made during a field paleontology class taught by Martin, which included six graduate and undergraduate students who visited dig sites around the Northwest.
The Granger-area site was the last stop on their itinerary, and it is one of the most important scientific sites in the state, Martin said.
The fossils they dug for are the remains of small fish and other aquatic life, and rodents
that inhabited what is now the Yakima River basin from five to 10 million years ago.
The site gives students the chance to learn how to excavate and what to look for.
“The material here is very delicate and very small,” Martin said.
Because of that, the excavation there often proceeds very slowly.
“The key to this whole site is patience,” said Martin.
The material there is sometimes examined a millimeter at a time.
The site is part of an old riverbed, Martin said, and the flow of the water broke up and separated the skeletal remains of the animals there when they died.
“I doubt we’ll ever find a complete animal,” Martin said.  
He said the Granger dig had two main objectives.
One is to collect fossil specimens for examination and study and the other is to collect samples of the volcanic ash present there to establish the age of the site as closely as possible. 
The big find of the day was fossil fragments of what was believed to be a turtle, found by Sarah Knight, an undergraduate member of the team.
Team member Ryan Tucker, a graduate student who will soon begin a PhD program in Australia, said turtles are important because they can serve as climate and environment indicators.
“They can’t migrate and they can’t take the cold,” said Tucker.
So their presence at the site gives scientists a means to gauge the temperature and other environmental factors at the location millions of years in the past, and helps scientists “build a local ecology” for that period, Tucker said.
When local ecologies from a variety of sites across the continent and around the world are studied, a picture begins to emerge of what the planet may have been like in various epochs.
Scientists can then begin to better understand how plants and animals respond to climate and other environmental changes, Tucker said.
Martin, who took his doctorate at the University of Washington, said he has been visiting the Granger site since 1974.
Other members of the class were Ed Welsh, Rachel Short, Jeff Martin, and Tom Linn.