| Abstract: | A recent test has shown that planktonic foraminifera, living for at least part of their life in the surface waters of the oceans, are limited to certain temperature zones. Since their evolution has been relatively slow, their calcareous remains, which accumulate on the deep-sea floor, can be analysed in samples taken from cores and temperature oscillations can be traced into the past by the percentage of warm, temperate and cold forms. It has been demonstrated that a count of a thousand specimens in each sample is all that is necessary to obtain these results. |
