ADVA^fTAGE OF TERMS OVER PHRASES 113 



understanding regarding the ground to be cultivated and the means to be 

 employed in geography, the older but less developed sister science of 

 geology. 



It has already been shown that various terms, such as delta and vol- 

 cano, which undoubtedly belong under geography, are really only concise 

 names for things that result from a more or less complicated series of 

 processes acting through a longer or shorter period of time, so that if the 

 terms were expanded into their full meaning the resulting phrases would 

 be classified under geology by those of us who would place in that science 

 the explanatory account of the Front Eange with which this address 

 began. Let me illustrate this point more fully. 



If instead of saying "volcano" one should expand this simple word into 

 its whole meaning, there would be much to be told about the long con- 

 tinued action of a whole series of past processes ; there would first be an 

 explicit statement about the prevolcanic foundation; then something 

 about the initial stages of eruption, with their associated explosions, 

 earthquakes, growing cinder cones, outspreading lava flows, and far- 

 carried ash showers; there would be mention of intermediate periods of 

 erosion, with the outwash and deposition of torrent-borne volcanic ag- 

 glomerates on the neighboring lower lands; of renewed volcanic activity, 

 in which dikes split their w^ay upward, or in which the earlier volcanic 

 summit is engulfed only to be built up again higher than before, with 

 renewed explosive outbursts, with lava flows and ash showers that fill the 

 valleys eroded in the earlier cone, and so on over and over again, for a 

 volcano is a complicated affair. Surely no self-respecting volcano that 

 has gone through all these violent throes of growth and all these periods 

 of apparent exhaustion would be content to be thought of as a ready-made 

 article without a past. Indeed if a geographer says "volcano" without 

 more or less distinctly conceiving all this complicated series of past proc- 

 esses he confesses himself deficient in scientific inauguration. Further- 

 more, no volcano that has properly pla3'ed its destructive part in organic 

 evolution would be satisfied with an account which made no mention of 

 the way eruptions had repeatedly overwhelmed the organic inhabitants of 

 its district, burning and burying successive populations that had mistaken 

 the foundation or the fianks of the cone for a safe habitation. Indeed, 

 when we properly link volcanic growth with organic evolution, we may 

 come to discover that the existing population of a large volcanic district 

 recently and repeatedly overwhelmed by lavas and ashes, as in central 

 Mexico, is chiefly made up of such plants and animals as could repeatedly 

 return after repeated destructions and expulsions, and honce that in such 

 a population we should find for the most part active settlers, while slow 

 VIII — Bull. Geol. Soc. Am., Vol. 23, 1911 



