Fossil Cycad

Object/Artifact

-

Crater Rock Museum

Name/Title

Fossil Cycad

Entry/Object ID

78.58.473

Description

Assemblage Zone: sandstone sediments Chemical Composition: Si O2 Crystal System: Hexagonal Description: Family: Cycadaceae Genus: Cycadopsida Common name: Cycad Age: Jurassic Location data: Big Thompson Canyon, Henry Mountains, Utah USA Description: A 1 1/8" thick slice of a half slice of petrified wood (cycad) from Escalante, Utah. Polished side shows wood in olive, greys, black, red, orange and golden cream. Probably from Jurassic period, Mesozoic era. l Size:5.250"x 5.500"x 1.250" CYCADS **These Jurassic petrified cycads were collected from the Morrison Formation in Utah and among the most colorful fossil cycads in the world. Cycads have an extensive fossil record extending back 300 million years. Cycads today are very slow growing and many are very long-lived, some living to 1,000 years old. Unlike ferns, which reproduce by spores, cycads reproduce by seeds. In fact, cycads are one of the oldest seed-bearing plants. like pin trees, cycads produce cones: but while pine trees produce both male and female cones on the same tree, cycads are "dioeceious" -- each cycad is either a male or female plant that produces male or female cones. Femles cycads from the Jurassic had cones embedded in their trunks, while cycads living today bear cones in the center of the sprays of frond-like leaves at the tops of their trunks. Modern cycad cones look like pine cones, excetp that they are huge, some weighting 75 pounds Type of Fossils Present: Plants Fracture: conchoidal Grain Size: Fine Hardness: 7 Quartz Lithofacies: Alluvial System Luster: Glassy Occurrence: Fossilization occurs when the plant is buried and minerals dissolved in the groundwater, over millions of years, replace the original plant tissues. Fossilized cycads may occur as leaves or trunks. The trunks somewhat resemble overgrown pineapples turned to stone because of the armor of old leaf bases which protected them in life. Leaves are usually found as carbonized impressions in the rock. Pressure: Low-Moderate Rock Color: Medium Rock Origin: Post-depositional Rock Type: Sedimentary Specific Gravity: 2.6 Surface Process: Not apparent Streak: white Temperature: Low Texture: Mircrocrystalline Variety: The cycads are a group of very primitive ligneous plants bearing a superficial resemblance to palms, although they are not at all related. Cycad are often refer to as a "living fossils," since this group of plants had reached its highest point of evolution during the early Jurassic about 200 million years ago since then cycads have been declining without showing any appreciable changes in their evolution. Present cycads have many characteristics similar to the fossil cycads of 240 million years ago; thus, the name living fossils. Apparently, during the Triassic and Jurassic periods, the cycads enjoyed an abundant distribution, because nowadays, although often very localized, the existing species appear in places such as Polynesian, Madagascar, Japan, South Africa, tropical Africa, Australia, Mexico, Cuba, and Central and tropical America, which gives us an idea of the world-wide distribution that they had in the past.

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: 1978.58.473

Dimensions

Width

5-1/2 in

Depth

1-1/4 in

Length

5-1/4 in

Dimension Notes

Dimension taken at widest points

Location

Location

Container

Right

Drawer

Top Shelf

Shelf

Center

Cabinet

Case#104

Wall

East Wall

Building

Mentzer Hall: Petrified Wood Room

Category

Permanent

Location

Shelf

bottom left of cente, bottom left of cente

Wall

Eastern

Room

Petrified Wood

Building

Mentzer Hall: Petrified Wood Room

Category

Permanent