Welcome

Welcome to the Little Jerusalem EarthCache Series. This series was placed at the request of the Stae Park so it is important that you follow all rules to demonstrate how responsible geocachers are with the environment. Please stay on the trail and follow all rules as posted.  At no point, should you touch, collect, or disturb the environment except where specifically directed. Please enjoy this series of EarthCaches responsibly. There is a $5 day fee to access this park. 

Earth Science Lesson

At GZ, the overlook, you should easily be able to find many examples of fossils. For more information on fossils read below. Use your observations along with the information below to answer the  questions. 

Fossils and Fossilization

Fossils are the remains or evidence of ancient life. Fossils come in various forms--from bones and shells to carbon imprints to footprints and burrows. Fragmented or whole, fossils provide vital information about earth and its inhabitants millions, even billions, of years ago.

Finding fossils is relatively easy, but becoming a fossil is not. Only a tiny fraction of organisms that have lived during the past 3.8 billion years are preserved as fossils. Instead, most are eaten, attacked by bacteria, fragmented, crushed, or dissolved or worn away by water movement--to name some common fates.

Several factors favor fossilization, but probably none is more important than the possession of hard parts--sturdy bones in vertebrates, thick shells in invertebrates, wood and seeds in plants. Hard parts hold up better to decay and destruction than such soft tissue as muscles and organs. Thus, for example, we find many more clams than worms in the fossil record.

Rapid burial is also essential for fossilization; it protects an organism from being eaten by scavengers, attacked by bacteria, or battered by running water or wave action. Generally, plants and animals that live in or fall into water are more likely to be buried quickly when they die. They settle to the seafloor, lake bottom, or riverbed and are buried by the sediment that accumulates over time. This is one reason that aquatic organisms are far better represented in the fossil record than those that lived on land.

Even if an organism is fossilized, it may subsequently be destroyed by ongoing geologic processes such as mountain building and erosion. If a fossil escapes obliteration, it then becomes part of the fossil record. Still, the odds are decidedly against preservation as a fossil. Most organisms lived, died, and vanished without a trace.

Fossils in Kansas Rocks

Kansas has many fossil--bearing rocks at the surface, mostly limestone, sandstone, and shale. Limestone is composed mostly of the mineral calcite, or calcium carbonate (CaCO₃), which is secreted by various animals and plants--such as oysters, corals, and algae--that live in aquatic, mostly marine, environments. Sandstone and shale, on the other hand, are made up of sediment that eroded from other rocks. Sandstone, as its name suggests, is made up of sand grains, bonded together by natural cement. Shale, on the other hand, is composed of compacted clay- and silt-sized particles too small to be seen without a microscope.

Most limestone (in Kansas and elsewhere) was deposited in warm, shallow seas, such as the ones that covered Kansas intermittently during the Pennsylvanian, Permian, and Cretaceous periods. These warm, shallow seas were not only good for making limestone, but also for preserving the organisms that lived in these seas. The calcium carbonate ooze that collected on the sea floors made a perfect burial ground. Thus, Kansas limestone contains many fossils; indeed, some are made up almost entirely of fossils.

Sandstone and shale also formed in marine environments. During periods of erosion, sediments were washed from the land and carried into the sea by streams. The coarser sediment, such as sand, settled out first, while the finer-grained clay- and silt-sized particles were carried farther out to sea. Thus, sandstone beds may indicate deposition on or very near shore, whereas layers of shale indicate deposition a little farther from shore.

Common Invertebrate Fossils

Ammonoids

Ammonoids are extinct squidlike creatures that lived inside an external shell. They are related to the chambered Nautilus, and, like Nautilus, most were probably good swimmers, moving through the water by means of a kind of jet propulsion and eating fish, crabs, and other shellfish.

Ammonoids evolved during the early part of the Devonian Period, about 415 million years ago, and died out about 65 million years ago, during the mass extinction at the end of the Cretaceous Period that killed the dinosaurs and many other land and sea animals. Ammonoid fossils (ammonites) are common in sedimentary rocks around the world and are somewhat common in the Cretaceous rocks of western Kansas.

Many ammonoid shells were coiled in the same plane, like a cinnamon roll; others had straight or erratically coiled shells. The external surface of some shells was ornamented with different color patterns, ribs, nodes, or spines, but this ornamentation is not always preserved.

Internally, ammonoid shells were divided into many chambers by a series of intricately folded walls. The pattern of the folding can be seen in many specimens in which the outer shell has been removed. The junction between the wall and the outer shell produces a line called the suture, and these suture patterns are unique to each ammonoid species (fig. 2).

Figure 2--Convoluted sutures are easily evident in fossil fragment of genus Baculites from Cheyenne County, Kansas.

Most Paleozoic ammonoids were golf-ball sized or smaller. At the height of their diversity during the Cretaceous, larger ammonoids, some with diameters up to 10 feet (3 meters), were common. Ammonoids are relatively common fossils in the Cretaceous outcrops of central and western Kansas and less common in eastern Kansas, where smaller fossils occasionally are found in Pennsylvanian and Permian outcrops (fig. 3).

Figure 3--Two ammonoid fossils: Goniatites (left) and Schistoceras missouriense (right) from Montgomery County, Kansas.

Brachiopods

Brachiopods are marine animals that secrete a shell consisting of two parts called valves. They have an extensive fossil record, beginning in the early part of the Cambrian Period, about 525 million years ago, and their descendants live in today's oceans.

The name brachiopod comes from the Latin words for arm (brachio) and foot (pod) and refers to a paired, internal structure, which specialists initially thought was used for locomotion. This structure, called the lophophore, is actually used for feeding and respiration and is common to all brachiopods. Another distinctive feature is their bilaterally symmetrical valves, in which the right half mirrors the left, different from the symmetry of clams (fig. 4).

Figure 4--Contrasting symmetries in brachiopods and clams.

Brachiopod shells come in a variety of shapes and sizes (fig. 5). The outer surface of the valves may be marked by concentric wrinkles or radial ribs. Some brachiopods have prominent spines, but these are usually broken off and are found as separate fossils.

Figure 5--Brachiopods commonly found in Kansas rocks.

Brachiopods are one of the most common fossils in the Pennsylvanian rocks in eastern Kansas and are common in the younger Permian rocks. In spite of their abundance in many Cretaceous rocks worldwide, brachiopods are almost never found in the Cretaceous rocks of Kansas.

Bryozoans

Among the most abundant fossils in the world, bryozoans are also widespread today, both in marine and freshwater environments, living at all latitudes and depths ranging downward to at least 27,900 feet (8,500 meters). Bryozoans are small animals (just large enough to be seen with the naked eye) that live exclusively in colonies.

Marine bryozoans show up in the fossil record in the early part of the Ordovician Period, roughly 470 million years ago. In Kansas, fossil bryozoans are common in the Pennsylvanian and Permian rocks of the eastern part of the state. Throughout their long history, marine bryozoans have been abundant and widely distributed geographically.

Bryozoans are sometimes confused with corals, which are also colonial. Like corals, most bryozoans secrete external skeletons made of calcium carbonate, which form the framework of the colony. Bryozoans, however, are more complex organisms than corals and generally do not build reefs.

Some bryozoans built colonies that grew from the seafloor in branching structures; these fossils look something like twigs. Other species erected netlike frameworks, while still other spread like a crust on shells, rocks, plants, and even other bryozoan colonies. Almost all the fossils are fragments of colonies; only rarely is an entire colony preserved. Bryozoans are common fossils in the rocks of eastern Kansas (fig. 6) and are less common in the Cretaceous rocks to the west.

Figure 6--Bryozoan fossils from the Topeka Limestone, Shawnee County, Kansas.

Clams and other bivalves

Clams and their relatives (oysters, scallops, and mussels) are often called bivalves (or bivalved mollusks) because their shell is composed of two parts called valves. Inside the bivalve's hard shell, the body consists of two lobes, one lining each valve. A muscular structure called a foot, present in most bivalves, is used for locomotion and burrowing.

Bivalve fossils first appear in rocks that date to the middle of the Cambrian Period, about 510 million years ago. Fossil bivalves come in many different shapes and sizes and have a wide range of external markings. Typically the right and left valves are symmetrical (see fig. 4). Some bivalves, such as oysters, do not have symmetrical valves.

The oldest fossil clams are generally the smallest; most Cambrian species are tiny, just large enough to see without magnification. Over time, larger species evolved. The largest--inoceramid clams from western Kansas--are as much as 6 feet (1.8 meters) in diameter. These extinct clams lived in groups on the sea floor of the shallow ocean that covered the interior of North America during the Cretaceous Period and are preserved in great numbers in the rocks of the Niobrara Chalk (fig. 7). Some of these huge fossils are covered with encrusting oysters. Others have been found with a variety of fish fossils between their shells, indicating that the fish used the giant clam as a safe feeding place.

Figure 7--Inoceramid clam Mytiloides mytiloides found in Lincoln County, Kansas.

In addition to the huge inoceramid clams, smaller clams and oysters are also common in the Cretaceous rocks of western Kansas, particularly in the Greenhorn Limestone. In the eastern part of the state, both marine and freshwater bivalves occur as fossils in Pennsylvanian and Permian limestones and shales.

Corals

Corals are simple animals that secrete skeletons made of calcium carbonate. They are close relatives of sea anemones and jellyfish and are the main reef builders in modern oceans. Corals can be either colonial or solitary. They live attached to the seafloor and feed by trapping small animals with their tentacles.

As fossils, corals are found worldwide in sedimentary rocks. The earliest fossil corals come from the Middle Cambrian, about 510 million years ago. In Kansas, they are fairly common in Pennsylvanian and Permian rocks.

Two groups of corals were important inhabitants of the Pennsylvanian and Permian seas--tabulate and rugose corals. Tabulate corals were exclusively colonial and produced calcium carbonate skeletons in a variety of shapes: moundlike, sheetlike, chainlike, or branching (fig. 8). Rugose corals are characterized by the wrinkled appearance of their outer surface. (Rugose comes from the Latin word for wrinkled.) Rugose corals may be either solitary or colonial. Because solitary rugose corals are commonly shaped like a horn, these fossils are sometimes called horn corals (fig. 9).

Figure 8--Tabulate corals (Thamnoporella) found in Labette County, Kansas.

Logging Tasks

1. Describe the fossils that you find. 
2. What do you think they are?
3. In what type of rock do you believe these fossils are located?
4. Post a photo of yourself, or a proxy, near GZ. No spoilers please. 

References

1. Brosius, Liz (2006). Invertebrate Fossils of Kansas. Retrieved from http://www.kgs.ku.edu/Publications/PIC/pic24.html

2. Whitehead, Cathryn (2020). The Rock Most Likely to Contain Fossils. Sciencing.com.  Retrieved from https://sciencing.com/5-types-fossils-6907983.html

3. Evers, Jeannie (2013). Fossil. National Geographic Resource Library Retrieved April 05, 2021, from https://www.nationalgeographic.org/encyclopedia/fossil/#:~:text=Fossils%20are%20the%20remains%20of,of%20organisms%20preserved%20in%20rock.