The company would have been hard-pressed to continue, since there is currently no place on the New York side of the river to store boats, and the relatively calm waters where the tours swing close to the majestic waterfalls are constrained by steep cliffs, rough rapids and the falls themselves.
I tiptoe to the edge and, lying down flat, my hands clutching the cliff's rough stone, I peer over the precipice to see something that would steal the sleep from the most heat-tired of eyes.
The Maid of the Mist operates in a relatively calm stretch of the Lower Niagara River that is hemmed in by the falls, rough rapids downriver and steep cliffs on either side.
At Big Sur, it climbs up the rough volcanic ranges, carving around cliffs with sheer drops to the thrashing ocean below, and leads on to the silver-grey foreshores of San Simeon, where elephant seals parp and loll, wriggling to inch themselves up the sand as the frothing tide approaches.
Moreover, the freedom to sleep rough (as Macfarlane does, on cliff ledges and beneath hedgerows) is unevenly distributed.
Start at Qasr al-Bint Temple at the edge of Petra's central city ruins, from where a rough trail trundles up the cliff of Al-Habees, weaving its way around the hill.
On the east coast of Barbados, the sea is very rough and there are a few cliffs to climb down to reach the shore.
They show images of "Rough Seas": giant waves cresting over cliffs and beaches, bombarding esplanades, grand hotels and piers and swamping heavily-clad early-20th-century daytrippers in clouds of spume.
His most emblematic is El Peine del Viento, or Wind Comb, a series of three pronged curves that reach out, claw-like, from a cliff above the often rough seas of La Concha Bay.
By last night 28 bodies had been recovered from waters so rough that volunteers standing on the 100ft cliffs were soaked by ocean spray and had to dodge debris flying up from the vessel below.
Cain said it was not a sheer cliff, but was a significant, rough slope.
