Flowstone forms from layers of calcium carbonate, deposited on rocks where water has flowed or dripped. This example comes from the Timpanogos caves in Utah.
This may allude to the Biblical story of Jonah, who was swallowed by a whale.
Though locations are never named, McCarthy does provide clues throughout The Road. Birch trees, and more specifically river birches, are common in North America, but are especially widespread across the southeastern quarter of the United States, from eastern Texas and southeastern Iowa to Virginia and northern Florida.
McCarthy repeatedly refers to the absence of fish in this post-apocalpytic world.
Fish populations – both marine and freshwater – are currently greatly threatened by pollution, loss of habitat, illegal fishing methods and overfishing. Read more about this unprecedented crisis at actionbioscience.org.
A post-apocalyptic world is almost impossible to imagine. In many ways, McCarthy's vision is founded in the knowable past, a time considered less civilised than the present.
A roadagent is one example; this 19th century term from the American west referred to a highwayman, a bandit on horseback who held up and robbed stagecoaches and vehicles on the road. McCarthy's ominous roadagents, however, hold none of the romance and glamour of those folk heroes of the Old West, like Wild Bill Hickok, Texas Jack and Buffalo Bill.
Though not the only advertisement or billboard mentioned in the book, this one is a solid clue to the book's setting, placing it firmly in the southeast US. Rock City is a tourist attraction, a natural rock formation on Lookout Mountain, near Chattanooga, Tennessee.
Emphasising the lack that the boy has always known, this episode also makes a stark statement about the consumer-capitalist society that came before the great unexplained catastrophe.
It also shows the great divide between the father and son, something that McCarthy no doubt considered with regards to his own young son, who was born when the author was in his late sixties, and to whom The Road is dedicated.