Sir,

No one is unaware that the term Indlandsis (with a capital I) was originally the name given to the ice sheet in the interior of Greenland. But the proper name has been used in France by geographers as a common noun (with a small i) to signify any ice sheet having the principal characteristics of the Greenland ice sheet, that is to say covering a large part or the whole of a continent, and as a result modifying the general atmospheric circulation. There are in geography many other well-known examples of this linguistic phenomenon; before becoming common nouns, karst originally signified a limestone region of Croatia, somma a crest of volcanic origin surrounding Vesuvius, erg two regions of dunes in the Sahara, bray a region of the Paris basin where there was a large anticline.

The terms nappe de glace (ice sheet), champ de glace (ice field) and calotte glaciaire (ice cap) are not satisfactory, since they can be applied to an ice mass of any size. However, the transition from glaciers and local ice fields to an indlandsis or vice versa as the climate changes, occurs in an irreversible fashion, as Brooks and Tronov have shown, and as I have described in my book (Reference LliboutryLliboutry, 1964–65, Tom. 2, p. 798–805). It is this discontinuity which allows us to classify glaciers and ice caps on the one hand and the indlandsis and their distributary glaciers on the other.

I hope Danish glaciologists will be so good as to lend us the word, and not to write ^®Indlandsisen.

17 February 1967