The interpretation of the extinct faunas that lie buried in the earth's strata' has engaged the attention of many students. One who attempts to unravel the mysteries of these buried records must have both imagination and inductive powers. From the remains, often fragmentary, of animals and plants in these strata, the student must build up, bit by bit, a picture of the animal and vegetable life that existed during the period, the kind of an environment in which it flourished, and the general character of the climate. As an example of this kind of interpretation I may mention the underlying rock of Chicago. This limestone is believed to have been deposited in a sea that covered a large part of the middle west. The water was shallow and its temperature relatively high. These facts are indicated by the presence of reef-building corals, which can live only in comparatively shallow water and in a warm climate like Southern Florida. It is to the interpretation of more recent faunas, however, that I wish to direct your attention at this time, faunas buried during the last great geological period known as the Pleistocene or Glacial Period-the Ice Age. In such interpretation the science of ecology is absolutely indispensable and without such aid grave errors may be made. Chicago furnishes one of the most striking examples of the value of ecology as an aid in the interpretation of these more recent faunas. In the northern part of the city, and extending northward to Wilmette, there once existed a large embayment of glacial Lake Chicago, the precursor of the present Lake Michigan. In this old lake bed there are many strata superimposed, which contain the remains of life that once lived here. Without a knowledge of the modern or recent ecology of fresh-water life it would be impossible to interpret these strata and rebuild the faunas as they were in life during the several changes that took place in this locality during the retreat of the great ice sheet and the final forming of the great lakes. Ecology applied to the fossil remains in these strata tells us that this bay was at first a part of the open lake without life, the waters being cold and the environment unfavorable; that there followed a period of low
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Sep 10, 1926
Frank Collins Baker 
