Glaciers to Great Lake:  Ohio would not be what it is today without the impact of glaciers during the Ice Age. Glaciers left behind more than just till deposits in Ohio, glaciers also helped make Lake Erie.  Check out this video and learn more about Ohio's Ice Age:
http://www.pbs.org/video/wptd-our-ohio-glaciers-great-lake/​
(Running time: Approx. 2 minutes) - WCET Cincinnati, Our Ohio series

Educators and Volunteers - "Natural Parks are America's Largest Classrooms!"
https://www.nps.gov/teachers/index.htm
Science in your National Parks:  https://www.nps.gov/nature/index.htm

Fossils and Fossil Hunting in Ohio
Once covered by vast tropical seas and later by giant glaciers, Ohio's landscape features an abundance of fossils. The glaciated portions of Ohio are home to Ice Age fossils, including plants and ancient mammals. But southwestern and northwestern Ohio boast a wider variety of much older marine fossils, including the official state fossil Isotelus maximus. In fact, the greater Cincinnati region lures paleontologists, fossil collectors, and rock hounds from all across the country and beyond who seek and have discovered some of the best fossil specimens in the world.  
- geosurvey.ohiodnr.gov/major-topics/fossils-in-ohio

Public Sites in Southwest Ohio - Visitors should contact park management staff prior to collecting to obtain any permits and/or rules that may apply.
Caesar Creek State Park (Clinton/Warren Counties) – Geology: Ordovician; fossils ranging from 450 to 500 million years old found in limestone forming the crest of the Cincinnati Arch. Collecting rules apply and a permit must be obtained at the U.S. Army Corps of Engineer's Visitor Center, which also features a display of fossils found at the park. For more information about fossil hunting at Caesar Creek, call (513) 897-1050.

Cowan Lake State Park (Clinton County) – Geology: Ordovician; fossils ranging from 450 to 500 million years old found in limestone forming the eastern edge of the Cincinnati Arch. Special permission to collect fossils must be obtained from Ohio State Parks. For more information, call (513) 897-3055.

East Fork State Park (Clermont County) – Geology: Ordovician; fossils ranging from 450 to 500 million years old in interbedded shale and limestone. Collecting rules apply. A permit must be obtained at the U.S. Army Corps of Engineers Visitor Center. For more information, call (513) 734-4323.

Hueston Woods State Park (Preble/Butler Counties) – Geology: Ordovician; fossils ranging from 450 to 500 million years old in limestone and dolomite forming the western edge of the Cincinnati Arch. For more information, call (513) 523-6347.

Oakes Quarry Park (Greene County) – Geology: Silurian; fossils around 425 million years old. Located in city of Fairborn, northeast of Dayton.  For more information, call (937) 754-3090 or see ( Ohio Geology, 2008 No. 2[800 KB PDF].

Stonelick State Park (Clermont County) – Geology: Ordovician; fossils ranging from 450 to 500 million years old in interbedded shale and limestone. For more information, call (513) 734-4323.
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Trammel Fossil Park (Hamilton County) – Geology: Ordovician; fossils ranging from 450 to 500 million years old in interbedded shale and limestone. For more information, call (513) 563-2985.

drydredgers.org/caesar_creek.htm
​www.fossilguy.com/sites/caesar-creek/caesar-creek-fossils.htm#trilobite

What are the oldest fossils?
The earliest evidence of life on earth is of marine animals, during the Precambrian era. But there is only sparse evidence of life before the Cambrian era. The oldest known Precambrian rocks, found in Africa and Australia, are believed to be more than three billion years  old. The fossils found among them are of the oldest known organisms on earth. Usually, fossils found in these old rocks are microfossils, such as elongated bacteria, Eobacterium and other water environment fossils. Bacteria represents the first stage of recognizable organized life and scientists have found well defined remains of algae and bacteria from nearly two billion years ago.

Where are most fossils found?
The most common fossils are found in sedimentary rock. Sedimentary layers act as evidence of the changing climate or movement of the continents during the passage of time. The Law of Superposition or Steno's law states that in a pile of undisturbed sedimentary rock, the oldest bed will lie at the bottom and the youngest on top. Layers of strata in different locations may have the same composition but carry fossils of a different time period, therefore a technique of zoning or an index fossil is used. Index fossils are specific animals or plants that had a broad geographical distribution but existed for relatively short periods of time. These fossils allow geologists to establish a parallel between layers of sediment. Some excellent guide fossils are ammonites; each species lived for relatively short periods of time but had such a broad geographical distribution. They can be found today in stratigraphic rock layers often separated by great distances. The appearance of the same ammonite in different layers in different localities gives evidence that those layers were deposited at the same time. Each time period is marked by an abundant radiation of many new life forms or the mass extinction of past life forms.
- www.ucmp.berkeley.edu/paleo/fossils/index.html

​​"Many world-famous paleontologists—geologists who study fossils—began their careers as youngsters collecting fossils in their native Ohio. Fossils from Ohio are important constituents of museum collections throughout the United States and Europe." - Fossils Collecting in Ohio ODNR GeoFacts
- geosurvey.ohiodnr.gov/portals/geosurvey/PDFs/GeoFacts/geof17.pdf

Types of Fossils:
Fossils undergo a variety of different fossilization processes, depending on the characteristics of the particular organism. There are various levels of fossil preservation, each containing its own clues pertaining to the organism. Fossilization at the cellular level varies in all organic compounds since not all cellular types are equally resistant to decay and decomposition. The same hold at the tissue level, where some tissue types are more susceptible to fossilization. The other two kinds include the organ level and organism level which provide information in the field of morphology and biology of the ancient organism. Although there are an endless number of categories, we will focus on the broader mode of classification.
Permineralization: is the occurrence of decay of organic substances and filling of mineral material into every cavity of the organism, still retaining most information about the fossil.

• Compressions: the two-dimensional compression which retains organic matter of the organism.
• Impressions: the two-dimensional imprint most commonly found in silt or clay, without organic material present.
• Casts & Molds: caused by deposits of sediment in cavities of organism, resulting in a three dimensional model.
• Compactions: preservation of organic material with slight volume reduction.
• Molecular fossils: deals with chemical data, preserving organic material, but providing no information concerning the structure of the organism.
• Freezing: ideal fossils that are rare, everything up to internal organs are preserved in cold storage.
• Amber: biological specimen that is encased in the hardened resin of a tree, in which the entire body may be preserved.
• Drying & Desiccation: fossils that have been thoroughly dried.
• Wax & Asphalt: almost as good as freezing, but with the usage of natural paraffin.
• Coprolites & Gastroliths: these categories deal with the indigestable remnants of meals.
• Trace fossils: typically formed when an organism moves over the surface of soft sediment and leaves an impression of its movement behind.

Additional Links:

Visit one of these websites to learn and research more about Ohio's Fossils. This can assist you in identifying your own fossils. Schedule a trip to fossil hunt or tour a museum to explore fascinating exhibits and examine rocks, minerals, and fossils from Ohio and around the world....plus much more.

DRY DREDGERS – A CINCINNATI-BASED ASSOCIATION OF AMATEUR GEOLOGISTS AND FOSSIL COLLECTORS

CLEVELAND MUSEUM OF NATURAL HISTORY

MUSEUM OF NATURAL HISTORY & SCIENCE – AT CINCINNATI MUSEUM CENTER
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ORTON GEOLOGICAL MUSEUM – AT THE OHIO STATE UNIVERSITY SCHOOL OF EARTH SCIENCES

Ohio's Geological Walk Through Time
Located at the Natural Resources Park on the Ohio State Fairgrounds, this exhibit offers a unique learning experience for anyone interested in Ohio's natural history, including fossils, rocks & minerals, and more.  www2.ohiodnr.gov/ohio-state-fair/geological-walk

University of Cincinnati Department of Geology

Covered in Shells (Greater Cincinnati):
thenaturalhistorian.com/2011/09/14/covered-in-shells-how-many-fossils-are-there/

Smithsonian Natural Museum of Natural History - The Department of Paleobiology:
http://paleobiology.si.edu/index.html

Virtual Museum of Geology:  www.virtualmuseumofgeology.com/
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Other State Geological Survey Web Sites (via AASG)

Geology Departments at Ohio Colleges and Universities

Ohio Rock and Mineral Clubs—Listing from the Midwest Federation of Mineralogical & Geological Societies.

Geology and Science Education Web Sites

Science Education Associations

​AGI Classroom Activities for K-12 Students

​"This is a typical flexicalymene retrorsa minuens trilobite fossil that can be found at Caesar Creek. Flexicalymene trilobites in the Caesar Creek area are reduced in size and most often found enrolled. They are usually the size of a fingernail or smaller. When searching for them, they superficially look like tiny brachiopods, so take your time, look closely, and you may find one!"

​Bryozoans are tiny colonial organisms, often mistaken for corals. The individual bryozoan is usually less than 1 mm in size. Bryozoan colonies can be branching, twiglike, fan-like, or encrusting. The entire colony is referred to as a zoarium. Some bryozoan colonies are smooth and others have monticules or bumps covering them. Each small opening or aperture was the home for an individual bryozoan or zooecium. The small animal seals the hole with a “door” or vestibule. They are difficult to identify without microscopic study. Sometimes the pattern of the apertures, size, or shape is characteristic and can be used for generic identification.

​Brachiopods are marine animals that have a shell made of two valves, which usually differ in shape and size. Brachiopods are closely related to the bryozoans. Brachiopod comes from Latin and means "arm" + "foot" and bryzoan means "moss animal"

Brachiopods are solitary marine organisms that live between two valves or “shells.” They are very common in the Cincinnatian rocks of Ohio. They are externally different from the pelecypods (clams) in that the left and right halves of the brachiopod shells are usually mirror images of each other (see picture below). Internally, brachiopods are completely different from the pelecypods. Brachiopods feed with a special filtering organ called the lophophore which is located between the valves and attached to the brachial valve. The pedicle extends through a small opening or hole in the pedicle valve and is used as an anchoring device. The interior of the brachial valve is important in taxonomic differences between various species.

​Crinoids are echinoderms that live on a long stalk, or column. Their crown is similar to an upside down starfish. Cross sections of the column usually have a tiny star within them. Columns and columnals are the most common parts found, although occasionally a crown or calyx can be found. It is rare to find the entire crinoid preserved. Crinoids are classified taxonomically by the characteristics of their crown, which makes identification of individual columns and columnals difficult unless the crown is attached.

The gastropods, or snails, are extremely diverse inhabiting marine, fresh water and terrestrial environments. Their shell can coil in a conical (conispiral) or in in single plane (planispiral).

Cephalopods are members of the phylum Mollusca and include squid, octopi and the pearly nautilus. Cincinnatian cephalopods were straight shelled squids. The siphuncle connects the cameras (chambers) together. The squid could pass air to the chambers via the siphuncle to make it float higher in the water or sink as it swam.

Phylum Cnidaria contains the corals, jellyfish, and anemones. Corals can be solitary or colonial. Corals have a rich fossil record because they excreted a hard calcium carbonate exoskeleton that preserves well. The Cincinnatian solitary corals are quite large, and are “horn” or “tooth” shaped. Individuals in the colonial corals are usually quite small, coralites being 1-3 mm in diameter.

What is Amber?
Amber is fossilized resin of a coniferous tree of early Tertiary. One of the differences between resin and sap is the latter's solubility in water since most of it is water from the xylem (water transporting system) of the tree.

In this type of fossilization, the organism is entrapped in a biologically inert environment and preserved as a whole. Intact insects are often found in amber, though they may be altered slightly. Many physical and chemical agents of abiotic environment (the oxidative air and temperature) and biotic factors (bacteria and scavengers) accelerate the decomposition of a dead organism. Avoidance of these factors aids in preserving the organism and in the amber formation.

The Process of Amber Formation:
Organisms fall or drop into the resin when it first exudes out of the tree. Essential oils, called Oleoresins, compose most of the first deposited resin. This substance is volatile and is often lost through the years. Additional resin then falls on top and gives the organism its typical suspended appearance. The resin then hardens through a process called polymerization and becomes less vulnerable to destruction. This hardened resin, called copal, has a higher chance of being fossilized than pliable resin.
As the copal ages, concentration of the essential oil decreases while the copal progressively oxidizes the resin and polymerization continues. The copal slowly turns into amber millions of years after the first entombment of the organism. The only way to differentiate between the two elements would be to put them through many physical and chemical tests such as UV light testing, burning, and various other tests.
The most famous examples of amber have come from the Baltic Sea region (Germany, Poland, Lithuania, Denmark, the former Soviet Union, Great Britain, Estonia, Latvia, and Holland). Because of the presence of microscopic air bubbles, Baltic amber tends to appear cloudy or milky. The hue varies with quantity and quality of the bubbles.
www.ucmp.berkeley.edu/paleo/fossils/amber.html