Tree Fern

Object/Artifact

-

Crater Rock Museum

Name/Title

Tree Fern

Entry/Object ID

78.58.81

Description

Chemical Composition: Si O2 Crystal System: Hexagonal Description: Family: Dryopteridaceae Genus: Tempskya Common Name: Tree Fern Age: Cretaceous Location data: South Dakota, USA Brule fm. Description: A 5/8" (1.5 cm) thick slice of petrified wood (fern) from South Dakota. Type referred to as "Temskya Fern". Piece is dark in color (shade in black), with "eyes" and several cracks extending from edge inward. Some small areas in light brown. Delmar says this piece is very rare. Probably from the Jurassic period (Mesoaoic era). Tropical variety - no growth rings Size: 5.750"x 7.500"x .675 Type of Fossils Present: Plants Fracture: conchoidal Grain Size: Fine Hardness: 7 Quartz 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: Tempskya is a form genus for the false trunks of a short to medium tree fern. The false trunk of Tempskya is composed of loosely organized leaf bases and stems encased in a dense mat of adventitious roots. A trunk looks similar to a poorly preserved palm trunk; the roots formed a conical false trunk that enabled the stem to assume an upright growth position. The roots were canniblistic and attacked older leaf bases and roots.

Collection

Petrified Wood Collection

Acquisition

Accession

78.58

Source or Donor

Delmar Smith Petrified Wood Collection

Acquisition Method

Donation

Other Names and Numbers

Other Number

Other Number: 1978.58.81

Dimensions

Width

7-1/2 in

Depth

11/16 in

Length

5-3/4 in

Dimension Notes

Dimensions taken at widest points

Location

Location

Container

Center

Drawer

Top Shelf

Shelf

Left

Cabinet

Case #104

Wall

East Wall

Building

Mentzer Hall - Petrified Wood Room

Category

Permanent