'I should have been surprised at the presence of a louse, but as aforesaid I had been stuffed full of traveller's stories on this point and was troubled thereon'
Here the 'stuffed full of travellers's stories' reminds one of Sir Richard Burton, who coined the phrase “Iceland on the Brain' for exaggerated claims about Iceland's various marvels. Burton's two-volume Ultima Thule, or A Summer in Iceland (1875) is a significant survey of Iceland's resources and problems in 1872. It was preceded by articles in British journals that caused WM to call Burton 'one of the curses of our hum-bugging society now-a-days.' (Kelvin, Letters, vol. 1, p. 159)
'the great cave of Surtshellir'
It is indeed a 'great' cave. A mile long and 15-20 feet deep, it is the largest string of caves ('hellir') in Iceland. WM added a short footnote here: 'Surtr is the god of fire,' a note that EMG lengthened with the following: 'the demon of fire, about whom so much is said in the Voluspa of the Elder Edda as leader of the forces of destruction on the day of Judgement.' Magnusson's notes, as here, are often helpful. At other times his deep erudition exasperated May Morris and Sydney Cockerell. See Aho's Introduction to Three Northern Love Stories. Surtr, in November 1963 (the same week that C.S, Lewis and John F. Kennedy died), boiled forth off the south coast of Iceland, creating an island that bears his name: Surtsey.'Gilsbank, Gunnlaug's stead . . . only some ten miles from us, though it will be be three weeks at least before we are there'
Morris was accurate in his forecast; they would be back at Gilsbank (now Gilsbakki) in exactly three weeks. Now they would go through the waste to the north coast and then out into Laxdoela country and then still further west to the very end of Snaefelsnes before turning back into the interior. They would arrive on August 22nd at Gilsbank, the stead of Gunnlaug. He was the skald-hero in the first saga that WM and EMG translated: 'The Story of Gunnlaug the Worm-Tongue Raven the Skald.' It appeared in The Fortnightly Review in 1869, and after extensive revisions in Three Northern Love Stories (1875). See Aho's Introduction to that volume for comments on WM's impressive mastery of skaldic verse.