67-i 



SCIENCE. 



[N. S. Vol. XV. No. 382. 



cutting or deposition — would seem to be 

 coastal currents of some sort. Such currents 

 must be either marine, or else subterranean 

 streams from the land, and it does not seem 

 altogether unlikely that they might be the 

 latter. The emergence of subterranean 

 streams might at least account, in some cases, 

 for the absence of deposits in the valley heads 

 and their nearness to the shore, if not for the 

 formation of the valley as a whole. The oc- 

 currence of an oil well in Vincente valley near 

 its head is significant in this connection. The 

 larger pre-Pliocene valleys of the Pacific coast, 

 which were much deeper than those of the 

 present time, were filled to a greater or less 

 extent during the Pliocene depression of the 

 coast, and have been as yet only partially re- 

 excavated. There are therefore at intervals 

 along the coast, deposits of loose materials exr 

 tending to a considerable depth below sea 

 level, and through these, underground waters, 

 under sufficient head, might find a submarine 

 outlet. 



It is possible that many if not most of the 

 valleys are due, not to any one cause, but to 

 several causes which have all contributed to 

 their formation or preservation. Much care- 

 ful and detailed investigation is necessary be- 

 fore the problem can be solved, and the state- 

 ments made here are intended as suggestive 

 rather than final. Such work as Professor 

 Ritter reports gives valuable information. 

 Observations in the vicinity of the valleys on 

 surface currents, their strength, direction and 

 persistence, and on the temperature and sa- 

 linity of the surface waters, and also similar 

 observations made, as far as possible, near the 

 bottoms of the valleys and in their neighbor- 

 hood, as well as a study of the materials cov- 

 ering their floors, might throw much light on 

 the question of their origin. Further than 

 this, detailed geological study of the mainland 

 adjacent to the valleys is necessary. The 

 physiographic conditions, both subaerial and 

 submarine, have been taken into account, to 

 a certain extent, in this discussion, but a fuller 

 knowledge of them is needed. Finally, as has 

 been stated elsewhere by the writer, each val- 

 ley must be considered by itself, since the ex- 



planation for any one is not necessarily the 

 explanation for all. 



W. S. Tangier Smith. 

 Washington, D. C. 



SHORTER ARTICLES. 



now MANY ONE-DOLLAR BILLS WILL EQUAL IN 

 WEIGHT A FIVE-DOLLAR GOLD PIECE? 



If the^ reader will answer the above ques- 

 tion in his own mind before going further he 

 will better appreciate what follows. This 

 (luestion was asked of a number of students 

 and professors, and the answers recorded. The 

 answers were surijrising and for the most part 

 extravagant. It seems that the idea of value 

 is so prominently associated with currency 

 that definite ideas of weight are somewhat 

 wanting, although most people have fairly 

 correct ideas of the weight of paper in other 

 forms. The number of persons answering 

 the question was 97. The average estimate 

 was 2,291 bills, the median estimate was 4.5. 

 In order to see if there is any tendency to 

 confuse the categories of value and weight 

 unconsciously, other persons were asked to 

 answer the question: How many five-dollar 

 bills will equal in weight a five-dollar gold 

 piece? Some ware asked a similar question 

 with reference to twenty-dollar bills. Putting 

 the fives and twenties together, there were 74 

 answers given. The average estimate was 97, 

 the median 25. The great difl^erence in the 

 averages is due to a half dozen very large 

 answers to the first question, but these do 

 not materially affect the median estimates, 

 which are the really significant figures. The 

 answers are all from males. A number of 

 answers were given by female students, but 

 their answers, either by chance or by nature, 

 were of such a great variety — ranging from 

 one to one million — ^that it seemed best to 

 leave them out in making the comparison. 

 After these calculations were made I received 

 answers, through the kindness of Professor 

 Templin, of the University of Kansas, from 

 two divisions of a class of both sexes. The 

 figures with reference to the one-dollar bills 

 show an average of 2,749, and a median esti- 

 mate of 99, while with the five-dollar bills the 



