The way I see it, two things were required in order that an era of incipient cultivation and domestication could begin. First, there had to be the natural environment of a nuclear area, with its whole group of plants and animals capable of domestication. This is the aspect of the matter which we’ve said is directly given by nature. But it is quite possible that such an environment with such a group of plants and animals in it may have existed well before ten thousand years ago in the Near East. It is also quite possible that the same promising condition may have existed in regions which never developed into nuclear areas proper. Here, again, we come back to the cultural factor. I think it was that “atmosphere of experimentation” we’ve talked about once or twice before. I can’t define it for you, other than to say that by the end of the Ice Age, the general level of many cultures was ready for change. Ask me how and why this was so, and I’ll tell you we don’t know yet, and that if we did understand this kind of question, there would be no need for me to go on being a prehistorian! [Illustration: POSSIBLE RELATIONSHIPS OF STAGES AND ERAS IN WESTERN ASIA AND NORTHEASTERN AFRICA] Now since this was an era of incipience, of the birth of new ideas, and of experimentation, it is very difficult to see its traces archeologically. New tools having to do with the new ways of getting and, in fact, producing food would have taken some time to develop. It need not surprise us too much if we cannot find hoes for planting and sickles for reaping grain at the very beginning. We might expect a time of making-do with some of the older tools, or with make-shift tools, for some of the new jobs. The present-day wild cousin of the domesticated sheep still lives in the mountains of western Asia. It has no wool, only a fine down under hair like that of a deer, so it need not surprise us to find neither the whorls used for spinning nor traces of woolen cloth. It must have taken some time for a wool-bearing sheep to develop and also time for the invention of the new tools which go with weaving. It would have been the same with other kinds of tools for the new way of life.