In much of the "Old World" (approximately Africa, Asia and Europe) the names of many places cannot easily be interpreted or understood; they do not convey any apparent meaning in the modern language of the area. This is due to a general set of processes through which place names evolve over time, until their obvious meaning is lost. In contrast, in the "New World" (roughly North America, South America, and Australasia), many place names' origins are known. Although the origin of many place names is now forgotten, it is often possible to establish likely meanings through consideration of early forms of the name. Some general conclusions about the nature of place names, and the way in which place names change, can be made and are examined below. It is also possible to distinguish regional trends and differences in the naming of places, as is also discussed below. Types of place name There are several clearly definable types of place name, the primary division being between the names of natural features and the names of human settlements. That the latter are 'places' is obvious. The case is slightly more ambiguous for natural features, depending on how exactly 'place' is defined, and what exactly the concept of a 'place' is used for. If, as is probable, natural features were originally given names to distinguish nearby hills, streams etc. from each other, then these features can be thought of as places, in that they represent distinct geographic locations. However, as names are applied on a larger scale, they may become less useful as place names. For instance, a relatively small, distinct upland valley (e.g. Swaledale) clearly represents a definable geographic location. However, the broad, extended valley of a major river, such as the Trent, is not easily understood as a single location. That notwithstanding, it is probable that the origins of the names of both settlements and natural features is the same, namely to distinguish one from another; and thus that both should be considered place names. Many other types of place name can be defined, for example those relating to tribal or personal names. Previously names relating to pagan religion were extensively studied as these were thought to be early. Another class studied was those relating to particular people, example: the Ancient British. The place names also can be based upon the nature of the occupation of the people in that area