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Laurel in Prince George's County, Maryland — The American Northeast (Mid-Atlantic)
 

Dinosaurs in Maryland!

 
 
Dinosaurs in Maryland! Marker image. Click for full size.
By Allen C. Browne, July 28, 2013
1. Dinosaurs in Maryland! Marker
Inscription. In 1842, English scientist Sir Richard Owen coined the term "dinosaur" to describe a group of ancient reptiles that inhabited the Earth from 230 to 65 million years ago. The discovery of the first dinosaur bones and the knowledge they reveal about the world these creatures lived in has captured the public's interest for nearly 200 years.

In 1858, miners discovered strange fossil bones and teeth in the iron-bearing clays near the Muirkirk iron furnace. Maryland State Geologist Phillip Thomas Tyson brought the bones to a meeting of the Maryland Academy of Sciences, where they were recognized as dinosaur teeth! Dentist and Academy member Christopher Johnston named the dinosaur Astrodon for the starburst pattern in the cross section of its teeth. The species name johnstoni was later added to reflect Johnston's contribution to its identification. The fossil dinosaur from Muirkirk became known as Astrodon johnstoni.

During the winter of 1887-88, more dinosaur bones were collected at iron mines in Maryland by paleontologists under the direction of Professor O.C. Marsh of Yale University. Marsh named these remains Pleurocoelus, and identified two different species. What he believed to be a small 12 foot long dinosaur, scientists now recognize as young specimens of a large, long-necked sauropod. Because
Dinosaurs in Maryland! Marker image. Click for full size.
By Allen C. Browne, July 28, 2013
2. Dinosaurs in Maryland! Marker
Astrodon is so fragmentary scientists are not certain whether is the same animal as Pleurocoelus.

Fossils-Important Clues to the Past
Dinosaur bones and teeth, and other fossils enhance our knowledge about prehistoric life and help to explain how plants and animals evolve over time. For example, fossilized impressions of dinosaur footprints indicate that some dinosaurs may have traveled in herds. Similarly, fossil evidence of dinosaur burrows and nests can teach us how dinosaurs lived and raised their young,. Fossils of leaves and trees help shape our understanding about the ancient environment in which these reptiles lived.

Dinosaur fossils are important clues to the past. They should be protected and preserved so that we can continue to discover and learn from them. If you are interested in getting more information about dinosaur bones and fossils at Dinosaur Park, please contact The Maryland-National Park and Planning Commission's Ranger Program 301-627-7755.
 
Location. 39° 4.245′ N, 76° 52.121′ W. Marker is in Laurel, Maryland, in Prince George's County. Marker can be reached from Mid Atlantic Blvd.. Click for map. Marker is in Dinosaur Park, 13201 Mid Atlantic Boulevard. Marker is in this post office area: Laurel MD 20708, United States of America.
 
Other nearby markers. At least 8 other
What was Astrondon Like? image. Click for full size.
By Allen C. Browne, July 28, 2013
3. What was Astrondon Like?
Astrondon was a sauropod, a long-necked plant-eating dinosaur that lived during the Cretaceous Period. It may havebeen a type of sauropod called a brachiosaur of a titanosaur. Like all dinosaurs, these ancient reptiles walked erect and reproduced by laying eggs. Scientists estimate that as adult Astrodon was at least 60 feet long and weighed several tons. In fact a six-foot, 220-pound thighbone was uncovered here at the Muirkirk deposit in the 1990's, confirming their immense size.
Astrodon johnstoni
Maryland's State Dinosaur

In May of 1998, the Maryland State General Assembly named Astrondon johnstoni the Maryland State Dinosaur. Astrodon joins other iconic state symbols such as the Blue Crab, Black-Eyed Susan, and Baltimore Oriole.
Close-up of image on marker
Painting by Gregory Paul
markers are within walking distance of this marker. Dinosaur Alley (here, next to this marker); Welcome to Dinosaur Park (a few steps from this marker); Dinosaur Park's Industrial Heritage (a few steps from this marker); Three Sisters: Close Knit Communities of the Laurel Area. (approx. 0.8 miles away); Abraham Hall: A Historic African American Benevolent Lodge (approx. 0.8 miles away); Iron Production: Maryland's Industrial Past - The Iron Making Process (approx. 0.8 miles away); When the Iron was Hot: African America Ironworkers of Muirkirk (approx. 0.8 miles away); Queen’s Chapel Methodist Church, Established 1868 (approx. 0.9 miles away). Click for a list of all markers in Laurel.
 
Also see . . .
1. Astrodon johnstoni. Discussed by dinosaur hunter Peter Kranz, at the University of Maryland. (Submitted on July 31, 2013, by Allen C. Browne of Silver Spring, Maryland.) 

2. Dinosaurs in Our Backyard. An interactive exploration of the dinosaurs of the greater Washington D.C. area at the Smithsonian. Many of the plants and animals shown have been found at Muirkirk. (Submitted on November 3, 2013, by Allen C. Browne of Silver Spring, Maryland.) 
 
Additional comments.
1. State Dinosaur of Two States
If Pleurocoelus and Astrodon really are the same creature,
Sauropod teeth from the Muirkirk deposit, now Dinosaur Park image. Click for full size.
By Allen C. Browne, July 28, 2013
4. Sauropod teeth from the Muirkirk deposit, now Dinosaur Park
Close-up of photo on marker
it has the distinction of having been the State Dinosaur of both Maryland and Texas. Pleurocoelus became the Texas State Dinosaur in 1997 but was replaced by Paluxysaurus in 2009.
    — Submitted July 31, 2013, by Allen C. Browne of Silver Spring, Maryland.

 
Categories. Paleontology
 
Four Astrodon teeth (bottom left). image. Click for full size.
By Allen C. Browne, July 28, 2013
5. Four Astrodon teeth (bottom left).
Close-up of illustration on marker
Plate XIII from Cretaceous Reptiles of the United States by Joseph Leidy, 1863
Astrodon femur cast extracted by Dan Chaney (left) and Peter Kroehler image. Click for full size.
By Allen C. Browne, July 28, 2013
6. Astrodon femur cast extracted by Dan Chaney (left) and Peter Kroehler
In June of 1991 Arnold Norden and his two children were searching for fossils at Murikirk and found a thighbone or femur, from an Astrondon. The bone was about six feet long and weighed about 220 pounds.
Close-up of photo on marker
Astrodon Femur image. Click for full size.
By Allen C. Browne, July 28, 2013
7. Astrodon Femur
Close-up of photo on marker
Dinosaur Tibia image. Click for full size.
By Allen C. Browne, July 28, 2013
8. Dinosaur Tibia
Dinosaur bone (tibia) extraction by Smithsonian Personel-- Fall 2006
Close-up of photo on marker
Dinosaurs Footprints image. Click for full size.
By Allen C. Browne, July 28, 2013
9. Dinosaurs Footprints
Close-up of photo on marker
Astrodon Tooth in Cross Section image. Click for full size.
By Joseph Leidy
10. Astrodon Tooth in Cross Section
Astrodon got its name (Astro (star) + don (tooth)) from the radial striations visible in this cross section of an Astrodon tooth.
from Leidy Cretaceous Reptiles of The United States, 1865,
Plate XX, figure 10
Dinosaur Park image. Click for full size.
By Allen C. Browne, July 28, 2013
11. Dinosaur Park
Astrodon johstoni appears on this sign for the Dinosaur Park.
 
 
Credits. This page originally submitted on , by Allen C. Browne of Silver Spring, Maryland. This page has been viewed 586 times since then and 9 times this year. Photos:   1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11. submitted on , by Allen C. Browne of Silver Spring, Maryland. • Bill Pfingsten was the editor who published this page. This page was last revised on June 16, 2016.
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