Note 69 — SECTION II. PHYSICAL GEOGRAPHY OF ICELAND.

The total number of recorded eruptions between A.D. 894 and 1862 is given by Baring-Gould, Introduction, xxi.-xxiii. There have been eighty-six from twenty-seven (reckoned in round numbers to be thirty) different spots, and the intervals of repose have varied in Hekla from six to seventy-six years; in Kötlu-gjá from six to three hundred and eleven. Such is the statement generally made. The fact is, however, that the exact number of the eruptions is not known, as the annals are more or less confused. The number of volcanic foci in Iceland is popularly and roughly laid down at twenty, and of these three are called active—Hekla, Katla or Kötlu-gjá, and the Vatnajökull volcano. It is a large proportion out of the total assigned to the world; the latter varies between the extremes of 167 and 300, showing the uncertainty of our present knowledge. Popular books speak of 2000 eruptions per century, or an average of twenty per annum.