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News.bytesNews.bytes Extra, issue 453  

Fossil from BLM lands featured at new museum

A new fossil museum in Central California features a mosasaur from the BLM’s Hollister Field Office.

Seventeen years in the making, the Fossil Discovery Center of Madera County celebrated its grand opening on Wednesday, Oct. 13, with hundreds of visitors. The event coincided with National Fossil Day. (text continues below)

large fossilized pointed head next to computer screen with fish-like sketch
Fossilized mosasaur head next to sketches of elasmosaurus and mosasaur.

The Fossil Discovery Center is located on Avenue 21 ½, just west of Highway 99 near Fairmead, or just south of Chowchilla. The center is open Tuesdays through Sunday, 9 a.m. to 4 p.m.

To date, 15,000 fossils have been recovered from the Fairmead landfill site near the discovery center, with twenty more years of active digging planned.  The Discovery Center is across the street from one of the largest deposit of mammal fossils on the West Coast.  The deposit has been dated to the Pleistocene (700,000 years ago). What started out as a planned two-week survey after a fossil was found by crews digging at the landfill has turned in to a 17-year scientific find, with numerous animals found on site. (text continues below)

A group of people examine a chunk of rock with fossils in an open area among grassy hills
Examining fossil remains at the site of the mosasaur discovery. 

large fossilized teeth in rock
Fossilized mosasaur teeth at the discovery site.

Bone fragments of the mosasaur were found by Erik Zaborsky, heritage resources program manager and tribal coordinator for the BLM's Hollister Field Office, while surveying for vertebrate fossils in western Fresno County.
“The mosasaur specimen was discovered in the late Cretaceous-aged Moreno shale at Panoche Hills in 2009 and excavated in 2010,” said Ryan O’Dell, Natural Resources Specialist in the BLM's Hollister Field Office.  A mosasaur is a large, Cretaceous-aged (65 million years ago) marine reptile that would have resembled a cross between an alligator and a dolphin. 

In the Moreno formation, vertebrate specimens are typically found within soft shale and the bone material is often poorly-preserved and encrusted with gypsum (a transparent mineral). The unusual fossilization mode within a concretion resulted in well-preserved bone structure. Due to the high scientific value of the mosasaur specimen, the decision was made to collect it. The specimen was excavated over two days in 2010. A local Boy Scout troop assisted with excavation during one of the days. Excavation revealed a large mosasaur specimen imbedded within a 2,000 lb. of concretion.

A single 1,500-pound block was loaded onto a sled and dragged with a truck to the base of the slope where it was then pushed into the truck bed. Several other large concretion blocks containing bone of the specimen were also collected. The 1,500-pound block was transferred to the new Fossil Discovery Museum where it will be prepared by paleontologists in a laboratory with viewing windows for visitors to watch the work in progress.

3 scenes: a crowd applauds, a color guard prepares to raise the flag, ribbon cutting
Scenes from opening day at the museum.

a skeleton stands on its rear legs
Other reconstructed fossil skeletons at the museum include this short-faced bear...

large land fossil skeleton on four legs
... this giant ground sloth ...

large four-legged fossil
... and this ancient camel.

- Dave Christy, BLM Central California District, 10/19/10

BLM-California News.bytes, issue 453

Last updated: 10-20-2010