As we continue our trip along old Route 66 from Chicago, Illinois, to St Louis, Missouri, we pass through Springfield, Illinois, home of late US president Abraham Lincoln. A side trip to see the associated historical sites is certainly in order. Further down the road we can hop off the interstate at Litchfield and experience the nostalgia of three miles of original Route 66 “Mother Road” highway. Then it’s off down the road to St Louis, our destination for today.
About 15 minutes east of St Louis, we come to the Cahokia Mounds State Historic Site. A great civilisation of Mississippian people lived here in ancient times. The population of Cahokia in 1150 was about 15,000, making it one of the greatest cities of the world — comparable to the populations of London or Paris at the time. Cahokia began to decline after 1200 and was abandoned more than a century before Europeans arrived in North America. Maintaining the houses, stockade and residential and ritual fires of the community would have required the annual harvesting of thousands of logs, and some scholars believe deforestation and over-hunting were causes for its decline.
I’ll drive as we travel along I-55 so you can gaze around as we cross over the Mississippi River into Missouri. The Gateway Arch is about a half a mile upriver. But don’t be distracted. If you look over the rails you can see dozens of barges moving up and down the river. Barge tows operating above St Louis on the upper Mississippi, and on the Ohio and Illinois rivers, must pass through locks so they are restricted in size to 15 barges, three across and five long. Barge tows headed downstream from St Louis can be much larger because they have no locks to navigate. A typical tow consisting of 40 barges lashed together, eight wide by five long, can carry a whopping 60,000 tonnes of cargo, the equivalent of six 100 car unit trains or 2400 large semi-trucks.
The Mississippi was used to move goods long before the towboats and barges we see today. For example, the inhabitants at Cahokia, the place we visited on the way here, maintained trade along the Mississippi with communities as far away as the Great Lakes to the north and the Gulf Coast to the south.
A wide range of bulk commercial commodities travel up and down the Mississippi River. Fertiliser from Florida goes upriver to grow the grain that comes down river. Salt from Louisiana is used on northern winter roads. Cement goes downstream for construction in Gulf Coast states. Other bulk commodities include ammonia, caustic soda, coal, molasses, pipe, slag, steel, twine … the list goes on and on. My favourite commodity is the 60 to 70 million tonnes of sand, gravel, crushed stone and building stone that is shipped on the Mississippi every year.
Most of the aggregate comes from pits and quarries located along the Mississippi and its tributaries. Let’s take a side trip a few miles downstream to visit one of those quarries that started in 1882 to make crushed stone for the Corps of Engineers river levee program. The limestone from this quarry comes from underground mines engineered for the final after-mining use of climate-controlled warehouses. The constant year-round temperature within the finished underground space is between 65oF and 72oF (18oC to 22oC), providing tenants with utility savings of up to 70 per cent. Pretty cool!
I hate to leave but we’ve got lots more to see along old Route 66. •
Bill Langer is a consultant geologist, formerly of the US Geological Survey.
Email bill_langer@hotmail.com or visit
www.researchgeologist.com