In the beginning of the year 1885 Aruba was surveyed as to its geology by K. Martin. Although this surveyer stayed only a few days on the island he succeeded in obtaining a clear view of the general geological features¹). It is, however, very well understandable that during our stay²) some corrections could be introduced in the geological map of Aruba and in the older ideas concerning the genesis of some rocks. Beside the above quoted publication by Martin some other geological literature about the island exists; the latter is not worth mentioning here being of no great importance.