LEPIDODENDRON – SCALE TREE

        Once you arrive at the location, please be respectful and take only photos and leave only footprints.  

        This area is covered with fossils and many of them are from the Lepidodendron Scale Tree.  I have found hundreds of fossis all along this roadside, many are found in large bolders such as the one you’re standing on, some in smaller rocks, some fragments and pieces.  This by far is the largest fossil that I have found along this roadside.

        To log this cache you must answer the following questions.  These should be answered prior to you logging this cache as a find!

1.  What is the approximate length and width of the fossil you’re looking at?

2.  What colors are present and how did they get these colors?

3. Do you see traces of any of the below listed minerals in this fossil?

4. How was this fossil formed (see below for the different preservation types)?

5.  What period did the Lepidodendron thrive?

 6.  According to the information below what is the lifespan of the Lepidodendron?

7.  Photos are encouraged but not required.  Please feel free to take a photo of you or your group at the site.

E-mail the above answers along with the GC number and cache name to the following e-mail address CLICK HEREor through my profile.  Any logs submitted without the above questions answered will be deleted.  Please send your answers then log your find.

Actual Photo of the Fossil

Lepidodendron— known as scale trees — were a now extinct genus of primitive, vascular, arborescent (tree-like) plant related to the lycopsids (club mosses).  They were part of the coal forest flora. They sometimes reached heights of over 130 ft., and the trunks were often over 6 ft. in diameter, and thrived during the Carboniferous Period. Sometimes erroneously called "giant club mosses", they were actually more closely related to today's quillworts than to modern club mosses.

The name Lepidodendron comes from the Greek lepido, scale, and dendron, tree.

Description and Biology

            Lepidodendron had tall, thick trunks that rarely branched and were topped with a crown of bifurcating branches bearing clusters of leaves.  These leaves were long and narrow, similar to large blades of grass, and were spirally-arranged. The vascular system was a siphonostele with exarch xylem maturation.

            The closely packed diamond-shaped leaf scars left on the trunk and stems as the plant grew provide some of the most interesting and common fossils in Carboniferous shales and accompanying coal deposits. These fossils look much like tire tracks or alligator skin.

The scars, or leaf cushions, were composed of green photosynthetic tissue, evidenced by the cuticle covering and being dotted with stomata, microscopic pores through which carbon dioxide from the air diffuses into plants. Likewise, the trunks of Lepidodendron would have been green, unlike modern trees which have scaly, non-photosynthetic brown or gray bark.

Lepidodendron has been likened to a giant herb. The trunks produced little wood, being mostly soft tissues. Most structural support came from a thick, bark-like region. This region remained around the trunk as a rigid layer that grew thicker, but did not flake off like that of most modern trees. As the tree grew, the leaf cushions expanded to accommodate the increasing width of the trunk.

Lepidodendron likely lived in the wettest parts of the coal swamps that existed during the Carboniferous period. They grew in dense stands, likely having as many as 1000 to 2000 giant clubmosses per hectare. This would have been possible because they did not branch until fully grown, and would have spent much of their lives as unbranched poles.

Reproduction

The branches of this plant ended in cone-structures. Lepidodendron did not produce true seeds like many modern plants. Instead, it reproduced by means of elaborate, encapsulated spores.  It is estimated that these plants grew rapidly and lived 10–15 years. Most species were probably monocarpic, meaning they reproduced only once toward the end of their life cycle.

Decline and extinction

By the Mesozoic era, the giant lycopsids had died out and were replaced by smaller Quillworts, probably due to competition from the emerging woody gymnosperms and other plants. Lepidodendron is one of the more common plant fossils found in Pennsylvanian (Late Carboniferous) age rocks. They are closely related to other extinct Lycopsid genera, Sigillaria and Lepidendropsis.

Facts about Fossils

Why Are Fossils Different Colors?

There are many underlying reasons for the presence of fossils with different colors. Aspects such as the age of the fossil, the soil in which it is deposited, its exposure to ultraviolet light via the sun, and many other mitigating factors are the reasons no two fossils bear exactly the same color.

There are many things that can change the color of a fossil, but the most controlling variable for fossil color is mineral exposure.

Copper

        The presence of copper in the soil surrounding a fossil can create a bluish or greenish tinge.  This is due to oxidization of copper that takes the place of organic compounds within the fossil. Just as a copper pot oxidizes when exposed to the air, so too will a fossil bearing copper oxidize to a greenish blue color.

Cobalt

Cobalt is a mineral that has been used since time immemorial for bestowing a blue or purple tint to dyes for fabrics and pottery. Just as cobalt can dye linen, its presence in a fossil gives it a blue or purple color. Cobalt is naturally blue, but turns a purple color when exposed to the mineral chlorine. This same effect is seen in fossils exposed to both compounds.

Manganese

Manganese is a mineral with a natural pink hue. When a fossil is deposited in soil and left there for thousands of years, its organic compounds are replaced by the minerals found in the soil. If the soil contains manganese, the fossil may gain a pink hue, or a washed out off-white color.

Silica

Silica is a compound with a natural white-gray color. Its presence in conjunction with other minerals can create fossils ranging in color from an almost brilliant white to washed-out variations of other colors, such as a blue-tinged white when a fossil is exposed to both silica and cobalt.

Sulfur

Sulfur is often present in soils and stratas where fossils are found. This compound possesses a yellow-white color and discolors fossils that are exposed to it accordingly.

Iron Oxide

Iron oxide-exposed fossils are probably the most commonly found colored fossils. Their red-brown tint looks like rust because iron oxide is rust. Iron in the soil is absorbed by the fossils, which then for all intents and purposes rust when exposed to oxygen, just as a piece of iron would.

How are fossils formed?

So how are fossils formed anyway? There are several processes that plants and animals or their parts can be preserved. No matter which way preservation occurs it takes a lot of luck, pure happenstance. Most living things are quickly recycled upon death. Scavengers and bacteria usually consume all but bones and shells.

The following is a list with descriptions answering the question “How are fossils Formed?” Generally the top of the list has methods that preserve best though their occurrence is seldom seen.

Freezing (refrigeration) - This is the best means of preservation of ancient materials. It happens only rarely. The animal must be continually frozen from the time of death until discovery. That limits the possibilities to cold hardy animals from the last ice age. There have been remarkable discoveries of mammoth and wooly rhinoceros found in ice from Alaska and Siberia. Specimens with flesh, skin, and hair intact have been found. Some of these finds suggest that they were flash frozen, with food still in the mouth and stomach.

Drying (desiccation) - Mummified bodies of animals including humans have been discovered in arid parts of the world. The soft tissues including skin and organs are preserved for thousands of years if they are completely dried.

Asphalt - In what is now downtown Los Angeles lies a 23 acre park called The La Brea Tar Pits, officially Hancock Park. Within the park are over 100 pits filled with sticky asphalt or tar. The tar pits were formed by crude oil seeping through fissures in the earth. The lighter elements of the oil evaporate leaving thick sticky asphalt.

The pits are famous for the number and high quality of Pleistocene fossils that have been pulled from the pits. The fossils date between 10 and 40 thousand years old. Asphalt is an excellent preservative. Bones, teeth, shells, the exoskeletons of insects, and even some plant seeds have been pulled from the pits.

Amber - Insects, spiders, and even small lizard have been found, nearly perfectly preserved in amber. Picture this scenario: A fly lands on a tree branch in an area that is now the Baltic sea. While looking for food it steps in sticky sap that the tree has made to protect itself from fungal infection.

As the fly struggles to escape it becomes more and more entombed in the sap until it is completely engulfed and suffocates. The tree eventually dies and falls into the swampy water from which it grew. Over the course of millions of years the tree along with countless others becomes a coal deposit and the sap with our fly inside is polymerized and hardened into amber. As more time passes the coal bed is submerged as the sea level rises. Eventually the currents uncover the coal bed, slowly eating into the Surface, little by little. When the erosion reaches the amber it floats to the surface because it is lighter than the salty water. It is then washed ashore where it can be found.

Carbonization (distillation) - In this process of fossilization plant leaves, and some soft body parts of fish, reptiles, and marine invertebrates decompose leaving behind only the carbon. This carbon creates an impression in the rock outlining the fossil, sometimes with great detail.

Permineralization -This is the most common method of fossil preservation. Minerals fill the cellular spaces and crystallize. The shape of the original plant or animal is preserved as rock. Sometimes the original material is dissolved away leaving the form and structure but none of the organic material remains.

Fossils have also been created by peat bogs, paraffin deposits, and volcanic ash.