Limb Cast

Object/Artifact

-

Crater Rock Museum

Name/Title

Limb Cast

Entry/Object ID

78.61.78

Description

Assemblage Zone: calcareous sediments Chemical Composition: Si O2 Crystal System: Hexagonal Description: Genus: Schinoxylon Common name: Pepper tree Age: Eocene Location data: Eden Valley, Wyoming USA Description: A 3/4" (1.9 cm) thick slice of a limbcast with some of original wood showing, from Eden Valley, Wyoming. Polished side shows a brown and black wood segements, there is grey agate along with several crystalline areas and open cracks with crystals, with some brown opaque rock. Delmar believed this was possibly a tropical tree and from the Jurassic period (Mesozoic era). Doug Foster identified this as a pepper tree from the Eocene epoch in the Green River Formation. The Green River Formation is a Eocene geologic formation that has recorded the sedimentation in a series of intermountain lakes environments created during the uplift of the Rocky Mountains by the Sevier (in the west) and Laramide orogenys. Size: 5.750"x 6.250"x .750" Type of Fossils Present: Plants Fracture: conchoidal Grain Size: Fine Hardness: 7 Quartz Lithofacies: Volcanic Ash / lake sedim Luster: Glassy Occurrence: Silicified wood, which is the fossilization and opalization of organic woody matter by the deposition of SiO2 in a anaerobic environment to prevent decay. This means that the wood must somehow be buried in an oxygen free enviroment, possibly in the silt-laden river or the bottom of a lake or buried by volcanic ash or volcanic related mudflow. The organic material is then replaced by (SiO2) silica, other minerals determined its colors. Pressure: Low-Moderate Rock Color: Medium Rock Origin: Post-depositional Rock Type: Sedimentary Specific Gravity: 2.6 Surface Process: Not apparent Temperature: Low Texture: microcrtystalline Variety: Petrified woods ar hydrous microcrystalline varieties of quartz that can be generally termed as chalcedony .

Collection

Petrified Wood Collection

Acquisition

Accession

78.61

Source or Donor

Delmar Smith Limb Cast Collection

Acquisition Method

Donation

Other Names and Numbers

Other Number

Other Number: 1978.61.78

Dimensions

Width

6-1/4 in

Depth

3/4 in

Length

5-3/4 in

Dimension Notes

Dimensions taken at widest points

Location

Location

Container

Left

Drawer

3rd Shelf

Shelf

Right

Cabinet

Case #105

Wall

North Wall

Building

Mentzer Hall - Petrified Wood Room

Category

Permanent