A couple of quotes from Journey To The Center of the Earth:
"Good horse! good horse!" he kept saying. "You will see, Axel, that there is
no more sagacious animal than the Icelandic horse. He is stopped by neither
snow, nor storm, nor impassable roads, nor rocks, glaciers, or anything. He
is courageous, sober, and surefooted. He never makes a false step, never
shies. If there is a river or fiord to cross (and we shall meet with many)
you will see him plunge in at once, just as if he were amphibious, and gain
the opposite bank. But we must not hurry him; we must let him have his way,
and we shall get on at the rate of thirty miles a day."
"At that moment our hunter returned, who had been seeing his horses provided for;
that is to say, he had economically let them loose in the fields, where the poor
beasts had to content themselves with the scanty moss they could pull off the rocks
and a few meagre sea weeds, and the next day they would not fail to come of
themselves and resume the labours of the previous day."
Editorial Note: the horses in Iceland don't shy very much because there's not
much to shy at, being mostly desert, the terrain being wide open, not many bushes,
very few trees.