Antecedents of modern earth science, namely geology, astronomy and physical geography, are to be found in the secondary curriculum of the nineteenth century. These had virtually disappeared from the high school curriculum by the time of the Great Depression. Geology and astronomy decreased as physics increased; physical geography fell when general science became popular. Causes offered for the decline of earth science include: the descriptive, non-laboratory nature of courses in this field; dependence by teachers on rote memorization methods of presenting poorly-organized factual material; and at the root of earth science's failure can be found inadequate teacher preparation. Earth science today, with a boost from the Earth Science Curriculum Project, is making rapid gains in the secondary curriculum. Failure by the colleges to rapidly institute programs for the preparation of earth science teachers could easily lead to another fall in the fortunes of secondary earth science.