In the 1950s, the impervious marine clay beneath Bates College helped to make Garcelon Field\u2019s old cinder track puddle-prone. (Courtesy Tom Leonard ’78)<\/figcaption><\/figure>\n\n\nAlong with Maine\u2019s many ponds and its rounded-off mountains, the Presumpscot Formation is a product of the Pleistocene Ice Age. About 35,000 years ago, according to the Maine Geological Survey, the Laurentide ice sheet began expanding into New England. At its largest, the sheet covered all of Canada and parts of the U.S. It grew thick enough to conceal Maine\u2019s highest mountain, Katahdin, which stands nearly a mile above sea level.<\/p>\n
So how does a glacier make clay? Friction is part of the answer. As the ice sheet advanced and retreated over time, it ground up and carried away whatever got in its path, even bedrock, which included feldspars, micas, and quartz. The smallest bedrock particles were fated to become clay. (The U.S. Geological Survey categorizes as clay those particles smaller than .002 millimeters, which are too small to see without a strong microscope.)<\/p>\n\n\n
And the other clay-making thing the glacier did was melt. In our region, the ice sheet reached its maximum extension near today\u2019s Georges Bank fishing ground about 20,000 years ago. Then, as the climate warmed, the retreat began, a slo-o-o-w melting back over thousands of years.<\/p>\n\n\n
Glacial meltwater washed away the rock particles the ice had picked up during its advance. Over the centuries, these and other detritus liberated from the ice sheet flowed into the sea and settled on the seafloor \u2014 which was far inland from the present coastline. That\u2019s because the unimaginable weight of the glacier, in a process called isostatic depression, smushed the land beneath it down to levels that were hundreds of feet well below current elevations.<\/p>\n\n\nThe light blue in this Maine map shows where the sea, driven higher by melting glaciers 14,000 years ago, once covered parts of Maine, including much of Lewiston and the Bates campus. Where the ancient sea encroached is approximately where marine clay is found today. (Map created by Alice Doughty)<\/figcaption><\/figure>\n\n\n\nAround 14,000 years ago, explains Bates geologist Mike Retelle, the meltwater was entering the sea at a delta at the south end of today\u2019s Lake Auburn. (Retelle and UMaine geologist Thomas Weddle co-edited a book on Maine\u2019s postglacial history.) <\/p>\n\n\n\n
\u201cGracelawn Cemetery is the top of that delta, so if you\u2019d been able to stand on the shoreline there, you\u2019d be looking at kind of a fiord environment,\u201d with water surrounded by sharply higher land, Retelle explains.<\/p>\n\n\n\n
Much of the region otherwise was submerged, including the low-lying portions of Bates \u2014 that is, virtually all of campus \u2014 and the neighborhood. At the sea\u2019s highest stand, Retelle estimates, the Bonney site was under 100 feet of seawater. And all the while, sand, silt, and clay were washing in with the meltwater and settling right where Bates and other institutions would later want to build things. (The nerve!)<\/p>\n\n\n\n
One indication that Presumpscot Formation clay is sited on an ancient seabed, as opposed to some lake bottom, is the presence of preserved sea animals, including marine mollusk shells from the genus Yoldia<\/i>, specimens of which turned up at the Bonney site during a June visit by Retelle, Beverly Johnson, and other geology faculty (a shell will be carbon-dated). In Augusta, the Maine State Museum has remains of a walrus and a mammoth found elsewhere in Maine clay.<\/p>\n\n\n\nWith a dime added for scale, this marine mollusk fossil, from the genus Yoldia and likely 13,000 years old, was found in the marine clay at the Bonney Science Center construction site during a June visit by Bates geologists, including Mike Retelle, Beverly Johnson, and Dyk Eusden \u201980.<\/figcaption><\/figure>\n\n\n\nThe dynamics of this whole business get confusing. Being depressed in an isostatic sort of way, the land surface was much lower during the glacier\u2019s reign \u2014 but so was sea level, because so much water was captive in glaciers around the world. As that water was released, sea levels rose. But so did land elevations \u2014 rebounding as the weight of the ice sheet went away. Today, the science center site is about 250 feet above sea level.<\/p>\n\n\n\n
Maine has a longstanding love-hate relationship with Presumpscot Formation clay. In the \u201cI Love PF Clay\u201d column, Maine ceramicists make plates and pots from it. In addition, its cohesiveness makes it useful for capping defunct landfills. (And for water retention in Lake Andrews, whose floor, beneath the duck deposits, is marine clay.)<\/p>\n\n\n\n
Of course, as mentioned above and below, Maine clay generally makes good bricks. (Morin adds a bit of sand to stabilize its formula.) In the 19th century, brickyards abounded in Maine. According to the Bangor Daily News<\/em>, the town of Brewer alone had 18 brickyards in the 1870s.<\/p>\n\n\n\nDuring the 1998 restoration of Lake Andrews, bulldozers and backhoes scraped the bottom of the pond down to the base of marine clay. (Marc Glass ’88\/Bates College)<\/figcaption><\/figure>\n\n\n\nAnd the \u201cHate\u201d column? While Presumpscot clay goes into bricks that are good to build with, it\u2019s not so swell as a substance to build upon. Compressed by the weight of a building, highway overpass pier, etc., a clay layer is prone to settling, and unpredictably so. While adding a frisson of adventure to your building project, these qualities often necessitate time-consuming and expensive \u201csoil improvements.\u201d<\/p>\n\n\n\n
Prior to the construction of Lane Hall, in 1963, President Charles Franklin Phillips reported to the trustees that \u201c[W]e swallowed hard when informed that the earth formation on the proposed site is such that 144 piles\u201d were needed to support the building\u2019s foundation. Phillips doesn\u2019t say \u201cclay,\u201d but we\u2019re thinking he meant clay.<\/p>\n\n\n
During site preparation for Kalperis Hall, a couple blocks down the clay deposit from Bonney Science, an initial round of injected soil reinforcements, each resembling a stack of doughnuts, proved inadequate. A second round used a different approach, known as GeoConcrete Columns, which created underground piers with a bulbous, onion-shaped base.<\/p>\n\n\nDuring summer 2019, 260 steel pipe piles like these were driven into the ground to stabilize the marine clay at the Bonney Science Center construction site. Here, a worker welds a second pipe onto the first to achieve the required length for driving. (Phyllis Graber Jensen\/Bates College)<\/figcaption><\/figure>\n\n\nBonney Science itself, being constructed on clay that\u2019s 50 feet or so thick (thicknesses of 200 feet have been documented in the Presumpscot Formation) required more than 200 so-called pipe piles to stabilize the soil.<\/p>\n\n\n
\u201cWithout that layer of clay, we likely wouldn\u2019t have needed to drive piles,\u201d says Chris Streifel, the Facility Services project manager overseeing the Bonney and previously the Kalperis\u2013Chu Hall projects. \u201cIt\u2019s definitely made life more challenging. It\u2019s mucky, messy, and slippery. It\u2019s not a fun substance to work with in general, but that\u2019s the nature of the business.\u201d<\/p>\n\n\n\n
Clay is the font of other dubious blessings. It makes a poor bed for parking lots, steam vaults, etc., which necessitates replacing it with more stable soils as part of infrastructure makeovers. Plants don\u2019t thrive in clay, so grounds crews planting a tree or shrub in a new spot will generally \u201cwant to put in some good organics and soil in place of clay to get things to root,\u201d says Jay Phillips, director of Facility Services operations.<\/p>\n\n\n\nCommons is one of many Bates buildings cloaked in waterstruck bricks sourced from local clay, made with the age-old technique of pressing soft wet clay into wooden molds. (Jay Burns\/Bates College)<\/figcaption><\/figure>\n\n\n\nThen there\u2019s drainage (not). Spring rain and snowmelt can collect in long-lasting puddles on campus that are big enough for the ducks to enjoy. Garcelon Field was infamously damp and mucky until drainage infrastructure was installed, in 1986. \u201cOnly the muddy condition of the field, which made it impossible to kick a goal from a touchdown, gave the victory\u201d to the University of Maine, The Bates Student<\/em> griped after a 7-6 Bobcats loss in 1912.<\/p>\n\n\n\nBut once water permeates clay, the clay wants to keep it. So Presumpscot Formation clay tends to be wet. Wet clay is plastic (hence the instability) and it\u2019s also, weirdly, both slippery and sticky, depending on which condition will cause the most inconvenience, especially to the people who work closely with it on a job site every day. A Google search on \u201cremoving clay from clothes\u201d generated 35,500,000 results.<\/p>\n\n\n\nFoundation preparation for the Gray Athletic Building in 1925 required removing the marine clay layer. Back then, it was done by horses pulling so-called Fresno scrapers, as seen here. (Muskie Archives and Special Collections Library)<\/figcaption><\/figure>\n\n\n\nA smaller but more meaningful number is the estimated count of brick \u2014 brick professionals don\u2019t pluralize with \u201cs\u201d \u2014 needed to sheathe the walls of the Bonney Science Center: 180,000, project manager Streifel estimates. <\/p>\n\n\n\n
The clay for those bricks (sorry, we need the \u201cs\u201d) is coming out of a mine in a field near a stand of trees in Auburn\u2019s Danville neighborhood. And not far from the field is the Morin Brick Company plant.<\/p>\n\n\n\n
On a July morning we met Morin\u2019s director of sales and marketing, Jason Lachance, whose family once owned the company and who started in the brickyard when he was 17. Our visit included a drive past the lot where freshly mined clay is rototilled, dried, and stored in heaps; and a distant look at the mine itself.<\/p>\n\n\n\nMade from clay mined locally, \u201cgreen\u201d bricks wait to be fired in the 2,000-degree, 270-foot-long kiln at Morin Brick Co. in Auburn, Maine. The firing gives the brick its familiar red hue by acting on iron in the clay. (Doug Hubley\/Bates College)\n\n<\/figcaption><\/figure>\n\n\n\nWe couldn\u2019t get close because the dirt road was paved with rejected bricks that keep heavy machinery from bogging down but are too jagged for passenger vehicles.<\/p>\n\n\n\n
Two employees of Shaw Brothers Construction, an earthworks contractor in Gorham, Maine, work the open-pit clay mine for Morin. \u201cIt\u2019s about 86 acres,\u201d Lachance said. \u201cWe\u2019ve been mining there now for approaching 30 years,\u201d with perhaps another five to 10 years of life left in the deposit. Given the need to find clay matching its established processes and customer interests, Morin is already taking steps to secure its next clay source. (The National Brick Research Center, at Clemson University, assays prospective clays for Morin.)<\/p>\n\n\n\n
Founded in 1912 and now Maine\u2019s last maker of clay brick, Morin also bills itself as North America\u2019s last manufacturer of \u201cwaterstruck\u201d brick. Where most brick is extruded, like dough from a pasta machine, waterstruck is made with the age-old technique of pressing soft wet clay into wooden molds. (\u201cWaterstruck\u201d refers specifically to the use of a jet of water to knock bricks out of the molds. Morin makes extruded as well as waterstruck.)<\/p>\n\n\n\n
The many Bates buildings cloaked in Morin waterstruck include the 2008 Commons and, on Campus Avenue, Chu and Kalperis halls, for which the company devised an extra-long brick. <\/span><\/p>\n\n\n\nA worker power washes the brick exterior of Bonney Science Center in December. (Jay Burns\/Bates College)<\/figcaption><\/figure>\n\n\n\n\u201cNo two waterstruck brick are exactly alike,\u201d Lachance explained. \u201cThat irregularity and random event, if you will, combined with a manipulation of flash in the kiln\u201d \u2014 extra-hot flare-ups \u2014 \u201cyield some wonderful ranges of colors. The Bates campus is a perfect example of what can be accomplished with waterstruck brick.\u201d<\/p>\n\n\n\n
Not to mention what can be accomplished with waterlogged clay.<\/p>\n","protected":false},"excerpt":{"rendered":"
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