Uncovering the World of the Cedar Creek Mastodon

Volunteers at the Cedar Creek Mastodon Site in Morrow County, Ohio., on October 25, 2014.  The exposed white plastic corrugated drainage pipe in the foreground triggered the excavation when the digging for it exposed two mastodon teeth in September 2013.   The soybean farmer installed the pipe to drain water flowing from upland (background) toward Cedar Creek Bog, which is not too far from this pipe, but not shown in photo.  In October, a trench was cut nearby to the bog to compare soil layers of the bog, excavation pits, and surrounding land.  (Photo by Don Comis)

At the time the Cedar Creek mastodon died, it was not far from a bog surrounding a quiet shallow lake, with abundant growth of algae and other plants, as well as freshwater mollusks, like ram’s horns snails.  This lake was once the deepest part of a large glacial lake that covered the Cedar Fork Valley in Morrow County, Ohio, about 15,000 years ago, when the last of the glaciers that had covered two-thirds of Ohio melted.  The glaciers are what carved out the U-shaped Cedar Fork Valley.

The large lake was created by the melting, during a warming period between 20,000 and 15,000 years ago.   The water was dammed in by glacial walls.  When those walls melted, the lake drained, leaving only the deepest remnant, which began to fill with mud from decayed peat.   As the climate warmed much more abruptly, the mud layer became a marl layer, lime-rich mud, within 500 years.   Around the time of the Cedar Creek mastodon, another cooling period began, abruptly changing the mud back to peat as water levels dropped further.

The lake that the mastodon and early man walked near was filled with plant and animal life.  The coarse gravels at the base of the mastodon site were the bed of a pre-glacial stream that fed the lake.

Entombing Bones and Artifacts

The mud with broken pieces of rocks above the gravel likely came from debris flows as water flowed from the surrounding higher elevations, “entombing the bones and artifacts under a slurry of muddy debris,” according to a preliminary report by Gregory Wiles and his College of Wooster (Ohio) Climate Change class.

Wiles sent the report recently to excavation leader Nigel Brush, associate professor of geology at Ohio’s Ashland University.  The report also says that the high calcium carbonate content of the mud helped preserve the mastodon bones and associated man-made objects.

The report presents results of analyses of soil cores taken in and around the bog and nearby mastodon site, soil mapping, observations of soil layers in  a trench dug in October, connecting the bog and the mastodon site, as well as radiocarbon dating.   Analyzing these cores reveals the periodic warming and cooling of the planet over the past 15,000 years, caused by changes in the earth’s movements as it rotates and revolves around the sun, changes in ocean circulation, and changes in greenhouse gas levels.

Last September, Wiles--with Tom Lowell and  his graduate student Stephanie Allard, at the University of Cincinnati, and University of Illinois student Jacklyn Rodriguez--collected the sediment cores from the bog.  Earlier, in August, the College of Wooster students had used soil probes to map soil depths down to 20 feet in the bog.

Two Million Years of  Climate Change

The report’s introduction says that, “The Earth has spent the last 2 million years in a state of constant flux, moving between 20 periods of intense cold and glacier cover and periods of warming and glacial melt.”

Wiles and his students also participate in a tree ring project that seeks answers to the question of whether the widespread deforestation and the draining of wetlands by the early Ohio settlers could have caused a major drought in the early 1800’s, revealed by studying tree growth rings in old trees throughout Ohio.  Their blog  says:  “This question is relevant to the ever-present striving of climate scientists to investigate the relative roles of natural climate variability and anthropogenic [caused by man] change.”

Many of Ohio’s  trees date back to the 1600s, including some at Kenyon College  in Gambier, Ohio, near my Apple Valley home.  The group studies old trees, including places in Wayne County, such as the Johnson Woods State Nature Preserve  as well as the Secrest Arboretum, and on the campus of the College of Wooster.

The group made its last visit to the mastodon site on Nov. 13, also reported on the group’s blog , which includes more information as well as photos and a  "Tree Detective" video on the tree ring project.  Project participants also document the ages of barns as well as changes in climate by examining the tree rings from core samples taken from barn beams and comparing them to old living trees around the barn and throughout Ohio.

I have a website where I post information and photos on archaeology finds as well as all other aspects of Nature and natural history.  I began this blog and website to catch the spillover from the monthly stories I write for the Apple Valley Cider Press, mainly a regular "Nature Article" feature.  All of my writing is done on a volunteer basis.

Mastodon Dig Turns to Lab for Answers

A look at the Nov. 9, 2014 mastodon dig.  It's likely that some or all of the mastodon bones were washed into the excavation site from upland drainage thousands of years ago.  (Photo by Don Comis)

You can see how cold it was on Nov. 9 by the winter clothing worn by volunteers.  (Photo by Don Comis)

As the search for mastodon bones on a soybean farm in Morrow County, Ohio, winds down before winter, the work shifts to a lab at Ashland University where the excavated materials will be analyzed to decide if it’s worth continuing the excavation in the spring.

Excavation leader, Dr. Nigel Brush-- Ashland University associate professor of geology--wrote in an e-mail answer to my questions, that the lab tests “will provide the final answer” as to whether the mastodon was killed and butchered by Paleo-Indians, as it appears.

Right Site?

Even if the answer is “yes”, the next question is whether the excavation site is the butchery site.  Brush wrote that, “Based on the geological work that is being done at the site, it is appearing more and more likely that the bones were brought to their present location by a debris flow from a site at a higher elevation. “  He added that an upland kill and butchery site doesn’t make as much sense as the current excavation site, which is right near the remnants of an ancient bog where the animal could have been trapped in the soft sediment by its weight.

The bog traces back to the Pleistocene era when it was a muddy glacial lake.

Students from Ohio’s Wooster College’s Climate Change class sank a probe more than 20 feet into the mud, gaining a record of environmental change over about the past 15,000 years.   Brush said, “They also found possible evidence for an old preglacial stream channel running through the bog."

Discovering the Ice Age

Students from Brush’  'Discovering the Ice Age” class are also among the volunteers on the dig.  

Since the skeleton parts found so far are very crushed and shattered, the focus of the excavation shifted after the first month, from recovering a complete skeleton for exhibit, to finding evidence of Paleo-Indians killing and butchering a mastodon.

Brush’s e-mail to me continued, “We have ample evidence from Ohio and surrounding states that Paleoindians were present during this time period.  Butchery sites are not as common, although their number is steadily growing (due to the work of Dan Fisher at the University of Michigan, and other archaeologists).

Paleo-Indian (also written as "Paleoindian") is the term for the first people to arrive in North America, about 16,000 years ago, near the end of the Ice Age.  The website www.Indians.org says that, “Their name, Paleo, actually comes from the Greek word “palaios,” meaning ancient.”

Tools, such as flint scrapers, used to possibly butcher the mastodon are being sent to another lab for DNA analysis to test for mastodon blood.  At the Ashland lab, bones and other materials are being power washed with water and examined for cut marks made by butchering tools.

Scavengers

Brush wrote, “There are a lot of gnaw and bite marks on the bone”, suggesting the possibility that the mastodon merely died of old age, its corpse eaten by scavenging animals.  But, it’s also possible that the scavengers were just mopping up what was left after the Paleo-Indians butchered it.

On Nov. 9, volunteers found another possible hammerstone, a large round stone used to as a hammer or maul to crush things.  Amateur “surface hunters” identify hammerstones by the pecks or pockmarks caused as the stones are pounded on things.   The latest hammerstone was found in the same plot where at least one other hammerstone was found.  Volunteers also found possible vertebrae on Nov. 9.

We also found more pieces of flint and fragments of bones, including small pieces of tusk.

Other items found since the dig began include possible leg bones, ankle bones, rib bones, jaw bones, wrist bones, and all four lower teeth of the mastodon.   And we found pieces of flint brought to the area by man from other parts of Ohio as well as pieces of charcoal that could have come from fires used to cook parts of the mastodon.  A possible fire pit was also found.

As far as I know, the only proven weapon found was a tiny projectile point (a “Merom Expanding Stemmed point “)—a Stone Age spear or arrow head—that belonged to Native Americans who arrived long after the mastodon was extinct.  While the mastodon dates back to beyond 8,000 B.C., the projectile “only” dates to between 1,600 B.C. to 810 B.C.

Mastodon On Its Last Legs

An analysis of the mastodon’s lower four teeth by volunteer Scott Donaldson showed that the mastodon had lived to a ripe old age that likely made it more vulnerable to predation by man or beast, as explained in my previous blog.  Donaldson led the work on restoring and preserving the teeth and served as one of the crew chiefs during the excavation.

In the fall of 2013, a soybean farmer found two of the teeth, two feet apart, after they were unearthed when a ditch was dug to lay drainage pipe.  This triggered the excavation which began Aug. 23, 2014.

The Nov. 9 dig was planned as the last dig before winter, but Brush later said that, weather permitting, he would schedule one more dig, after the weekend of Nov. 15-16.

Note:  I also have a website where I post information and photos on archaeology finds as well as all other aspects of natural history.  This blog and website began to catch the spillover from the monthly stories I write for the Apple Valley Cider Press, mainly a regular "Nature Article" feature.

Minnesota May Lose Two Icons--Moose and Loons

Story in current issue of National Wildlife magazine about the mysterious decline of moose in Minnesota and New Hampshire.

Illustration accompanying story of moose decline in National Wildlife magazine.   The causes may be a mix of  ticks and brain worms, aggravated by milder winters.

Global warming could rob Minnesota of not just its iconic loons, but also its moose.  And ,it could end the storied island life of wolves in Lake Superior’s Isle Royale National Park .

A story in the current issue of National Wildlife magazine describes the “deepening mystery” of why the “moose population in northwestern Minnesota has plunged from 4,000 animals to just 100.  Moose numbers are declining fast in northeastern Minnesota, too, and as far away as central and southern New Hampshire.”

The story also says that “some biologists believe” global warming “is behind the decline of moose in parts of Minnesota.”   Global warming may be working in conjunction with “a triple whammy of parasites, pests and predators.”   In New Hampshire, milder winters  have already increased tick populations to the point where they are draining all the blood out of moose.  Less snow cover also draws in more deer, and with them comes an increase in a brain worm that causes moose to “start walking in circles or just stand around until they become prey or die.”

The opposite is true on Isle Royale where there are no deer and therefore no brain worm.  There also soon may be no more wolves, which depend on the lake freezing periodically to allow wolves to walk to and from the mainland, to avoid inbreeding.   During the past 17 years, a “news of the wild” story in the magazine reads, “ice bridges formed only three times…As a result researchers have tallied the lowest number of wolves ever—an average of fewer than nine yearly during the past three years (the population typically fluctuates between 18 and 27 animals).”

The study of wolves on this island is now in its 56th year.  The study had found long ago that wolves maintain a healthy moose population.   Now moose kills by wolves have dropped to a record low and the moose population has doubled, to about 1,050, threatening the forest on the island, including the balsam fir that is the main food source for moose, demonstrating once again why healthy wolves are crucial to moose survival.

(Sidebar to article in Audubon magazine, listing loons as one of 314 bird species threatened by global warming.)

My copy of the October/November issue of the National Wildlife Federation's National Wildlife magazine arrived in the mail the day after I received Audubon magazine which said, "Minnesota will likely have no more loons in summer by the end of the century."

Extinction for 314 Birds, Including Eagles?

In the 1970s in Maryland I could only see bald eagles in cages.  By the 2000's, I lived a half mile from an eagle nest in Maryland, about 15 miles from the U.S. Capitol building.  And within two weeks of moving to Ohio, in 2012, I saw an eagle's nest about 5 miles from my new home.  Now, climate change threatens a second attempt at extinction for our Nation's symbol.  (Photo by Debbie Hurlbert, Howard, Ohio)

Pick a favorite bird that comes to your yard and it’s probably one of the 314 North American bird species at risk from climate change, according to a recent Audubon report, based on a  seven-year study of 588 species by Audubon’s science team.  The report is published in Audubon Magazine’s special issue, titled “Birds & Climate Change.”

The study suggests that “Nearly half of the bird species in the United States will be seriously threatened by 2080, and any of those could disappear forever.”

Shockingly this would also mean the reversal of one of the biggest conservation success stories, the revival of the bald eagle in my lifetime.  The study projects the bald eagle could lose 71 percent of its current range by 2050.  The report says, “It may see a 56 percent range expansion into areas opened up by global warming, but it will still need prey and nesting habitat in those new areas.”  That means that both their prey and their desired nesting trees must also survive global warming in their new areas, if the bald eagle is to survive there.

The same is true of the golden eagle, whose “breeding range is forecast to shrink 58 percent by 2050 and 79 percent by 2080, although it could potentially colonize new areas,” the report says.

No Loons in Minnesota

As the climate continues warming, all 314 species could lose their preferred habitats.  For example, loons are predicted to be totally gone from Minnesota as its climate warms, shrinking their non-breeding range by 63 percent and their summer breeding habitat range by 32 percent.   Shrink enough and the loons could be extinct.  That’s the basic idea with all the species-on-the-brink listed.

The study used hundreds of thousands of birdwatcher observations for the Audubon Christmas bird counts and the North American Breeding Bird Survey to determine each species’ “climate envelope”.  This envelope pinpoints the range of temperatures, rainfall amounts, and other climate characteristics of the habitats occupied by each species.  As the report states, “Then they looked for each combination of characteristics within sophisticated computer projections of the global climate, finding the future climate envelopes—and, by extension, the potential future ranges—of the species and mapping them to a resolution of 10 square kilometers.”

The study divides the 314 birds into two categories:  188 “climate-threatened” and 126 “climate-endangered”.   The climate-threatened birds” face losing more than half of their current range by 2080, although they have the potential to shift into new areas.”  The “climate-endangered” species, like the bald eagle, "are projected to lose more than 50 percent of their current range by 2050, with no net gain from range expansion.”

Although only nine birds species have gone extinct in continental North America in modern times, the losses were spectacular and caught the general public by surprise.  This is especially true of the passenger pigeon, which flew in such awesome numbers that no one believed they could become extinct.  But it happened.  On September 1, 1914, the last passenger pigeon, Martha, died at the Cincinnati Zoo, where it was kept as part of an unsuccessful attempt to save the species through a breeding program.

So, it’s appropriate for Ohioans to take the lead in in accepting  Audubon’s challenge to act now to prevent these predictions from being fulfilled.  After all, because Martha died relatively close to Columbus, the National Audubon Society chose the Audubon headquarters in Columbus to be the home of the sculptures of the passenger pigeon and four other extinct birds:  Labrador Duck, the Great Auk, the Heath Hen, and the Carolina Parakeet.  The other North American birds that went extinct since records were kept are:  Bachman’s Warbler, Dusky Seaside Sparrow, Eskimo Curlew, and Ivory-Billed Woodpecker.

Even Chad Robbins , the father of modern ornithology who organized the North American Breeding Survey, told me he never believed that the Kirtland warbler would be so close to extinction in his lifetime.

 I have never seen such an alarming issue of Audubon magazine—All 314 names of the threatened species runs along the top of 57 pages of the 102-page issue.

The Audubon study is undergoing peer review for journal publication.

Sampling Mud Down to 13,000 Years Ago to Shed Light on Mastodon's Grave

The two volunteers in the foreground are standing in a trench that reveals some of the soil layers in the excavation site that could reveal how the site was formed over the past 13,000 years or so--and how it fits in with the nearby bog that was once a glacial lake when the dead mastodon roamed its shores.   (Photo by Don Comis)

Pieces of mastodon tusk (left) and other bones (right) collected from the surface of the ditch area on April 26.   More complete bones should show up soon as we hone in on our quarry, during a dig that is in its third week.  (Photo by Don Comis)

On September 10, Ashland University's Dr. Nigel Brush sent me and other volunteers a link to Dr. Greg Wiles' latest blog (September 7) “on the sediment cores that were taken from the bog near the Morrow County (Ohio) mastodon site last Saturday, September 6.”  

Wiles will collaborate with the soil core team, giving his Climate Change students at the College of Wooster (Ohio) the opportunity of working with the cores over the next several weeks—a wonderful way to spend the first semester back at school!

The team—Dr. Tom Lowell and  his graduate student Stephanie Allard, at the University of Cincinnati, and University of Illinois student Jacklyn Rodriguez-- found many species of snails and possibly clams in one three foot (one meter) core sample of  lime-rich mud (clay “marl”).   In answer to one of the questions I e-mailed him after the September 6 dig, which I participated in, Dr. Brush said that that “Clay marls are light gray to whitish in color and are composed of a mixture of clay and small shell fragments of various organisms, such as gastropods (snails) and pelecypods (clams) that lived in glacial lakes.”

They team took samples—in 3-foot sections--down to 21 feet (seven meters).  The last 3-foot core sample represents the late glacial period, about 13,000 years ago, about the time when mastodons roamed the shores of the glacial lake that is now the bog.

The blog includes some nice photos, including one showing the soil layers (stratigraphy) in a trench cut in the nearby mastodon excavation area to locate the path of the machine that uncovered an 8-inch long mastodon tooth and pieces of other teeth and the jaw bone as it laid drainage pipe.

The caption says that “we hope to be able to link the bog cores to this site.  It may take a backhoe pit from the excavation to the bog to really understand how the stratigraphy here {in the nearby bog] links with the former lake.”

Another caption reads, “We look forward to the analyses of the cores…”

My Post-September 6 Dig Questions Answered

In answer to other questions in my e-mail, Dr. Brush said that the large bone, about 3- by 6-inches, might be part of the mastodon’s jaw bone, based on the bone’s angle, “but we haven’t been able to verify that yet.”

He also said that the charcoal found where we were digging could have “come from an earlier land clearance by one of the farmers who previously owned this property (i.e. cutting down trees near the bog and burning them).  There is always the possibility that the charcoal might also be from Native American campsites.  However, since we are still digging in disturbed soil from the recent ditch digging activities, as well as plowing, it’s impossible to say at this point.”

Big Bones Soon

The action continues this upcoming weekend.  On Saturday, a small team will dig down to the drainage pipe to find clues as to where we should concentrate our excavation work on Sunday.   The big bones should start showing up soon!

Whole Mastodon Bones Expected After Next Weekend

The main mastodon skeleton is likely near Unit 15, the middle left plot.  I worked with Jeff (wearing gray t-shirt) on Unit 16, the far left plot.  (Photo by Don Comis)

On Saturday, September 6, Ashland University students and other volunteers sift through all the soil carefully dug up by volunteers in the excavation plots.   (Photo by Don Comis)

In today’s e-mail (Monday, September 8) to those of us involved in the Morrow County mastodon dig, Ashland University’s Dr. Nigel Brush said that, “By the end of this coming weekend, we have a good chance of having found some intact bones (rather than bits and pieces).”

Dr.  Brush also said that “Dr. Gregory Wiles from the College of Wooster, Dr. Thomas Lowell from the University of Cincinnati, one student from the University of Cincinnati, and one student from the University of Illinois were also at the site this past Saturday in order to collect sediment cores from the bog for environmental analysis. “

Climate Change

He also said that earlier this fall, Dr. Wiles and his Climate Change students mapped the mud depth in and around the bog near the excavation site and found the sediment reached a maximum depth of over 20 feet.   The website describing this work says that the 20-plus feet  of mud is “a record of environmental change” over about the  last 15,000 years.   It also said that they found blue glacial lake clays overlain by a [lime-rich mud] (with snail shells), which is overlain by organic-rich mud. This sequence and its details will become clearer when the site is cored on 6 September."

Dr.Brush said , “They also found possible evidence for an old preglacial stream channel running through the bog.”

A photo caption on their website shows three of the mapping participants “Washing up and wondering about how the Mastodon may have met its fate along the shore of a muddy lake during the Pleistocene [era].”

Dr. Brush's e-mail report said that last Saturday they determined that many of the bones “we have recovered at the site have been from the disturbed soil in Unit 15, so it is likely that the remaining skeleton is nearby. “

8-Inch Long Teeth

As a result, they are changing the next excavation date to  Sunday, September 14, so a smaller team can finish Unit 15 down to the drainage pipe.   The machine that lay this corrugated pipe (tile) uncovered the 8-inch long mastodon tooth that launched this excavation.

Dr. Brush explained that ,”This work would allow us to see if there are any bones in the undisturbed soil on the east wall of the ditch.  If not, we may shift our excavation to the south or west on Sunday.”

Last Saturday, I was assigned to Unit 16 with Jeff, a fellow member of the Kokosing Chapter of the Archaeological Society of Ohio.  This proved to be a more promising site than Unit 4, where I worked  the week before.   Plus Jeff, who even though this was his first dig, has a lot of experience finding prehistoric artifacts of Native Americans on the soil surface.  So he has a good eye and spotted a lot of little fragments of bones.   He also seemed to have the big find of the day, with a piece about 6 inches by 3 inches that Jeff Dillard, who directed the excavation that day, said was probably part of a much bigger bone.  That bone and most of the other pieces found in Unit 16 were adjacent to Unit 15.

With some help, even I spotted my first small bone pieces while excavating.  And I found some more while sifting, increasing my confidence level.  The small pieces are easily missed or mistaken for stones.  I’ve learned a few rules of thumbs so far:

· Sandstone often impersonates as bone.

· Bones are usually not white.

· Bones make a duller sound, like hitting wood, when tapped with a trowel, while stones “sing” when tapped.  Bones also feel like wood.

· Bones usually have holes in their cross sections and lines on the outside.

I also learned that black areas can indicate charcoal which is interesting to archaeologists because it could indicate a possible cooking fire, either new or ancient, or it could just be from natural causes.

It was also fascinating to see a soil core about three feet deep that had been removed from the nearby bog for sampling.  The two university students who showed us the core said that the bog had once been a glacial lake.

The contractor who had uncovered the bones also visited the site last Saturday to check on our progress.  He told me he had found many things over the years, including a stone ball used by Native Americans for play, but never a mastodon skeleton.

He explained to Dillard and others  how his tile-laying machine worked, saying it cut a swatch 12-inches wide, but disturbed the soil on either side of the ditch as well, leading to more soil disturbance than the archaeology team had expected.  One of the dig volunteers told me that it would just shake the soil on either side, disturbing an area no more than four feet wide.  He also thought this shaking disturbance would only loosen soil, not break bones.

Brush Your Teeth, Not a Mastodon's!

And, I learned something that should make us all want to brush our teeth more and get rid of tartar:
The tartar on mastodon teeth covers particles of food they've eaten, helping archaeologists learn what they ate.   Just the thought of even just traces of food particles lasting that long should make us brush more!  But not when the teeth are thousands of years  old.  We were told not to brush any we found , to avoid removing tartar.

My excavation partner, Jeff, told me that a shoulder blade found earlier in the excavation showed the type of cut marks that could indicate the mastodon was slain by hunters and butchered.  Dillard noticed that some of the bones we found in Unit 16 also showed signs of having been broken long ago, possibly by butchering.

We scared up some living creatures in the plots, at least three frogs, one mouse, a beetle, and three frogs.

It was a nice cool day, with some misty rain, much more comfortable than the hot day the week before.

Eight of the volunteers were members of local chapters of the Archaeological Society of Ohio: Seven were members of the Johnny Appleseed Chapter and I represented the Kokosing Chapter—along with three Johnny Appleseed members who also had memberships in the Kokosing Chapter.  Ashland University students were also among the volunteers.

To see more photos of the mastodon excavation work go to my website and click on "Mastodon Dig" in the menu.