Soils, Civilisations and the March of Time
Most of the efforts of man to understand how the earth was formed and the nature of it have only yielded the following: first, there was a molten mass called "magma". This magma cooled leading to barren landscapes of mountains, deserts and steaming lava fields. The earliest forms of life were very primitive. Land plants appeared on the earth surface 400 million years ago and mammals 250 million years ago. Homo sapiens emerged within the last million years. On arrival man began to domesticate animals and till the ground in order to cultivate food crops. The soil referred to in this lecture can therefore not be different in definition from what Homo sapiens worked upon but the period of his activities and the impact of these activities on human culture and progress can only be extracted from recorded history. This period is more likely to be much shorter than one million years.