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SCIENCE 



[N. S. Vol. XXXI. No. 789 



moraine, rising 150 feet or more above the 

 valley floor. But there were certain associated 

 features which puzzled me at the time. Up- 

 stream from the supposed moraine the floor 

 of the cirque appeared to be deeply buried by 

 an accumulation of rock debris which was 

 generally as high as and near the head of the 

 cirque distinctly higher than the morainal 

 ridge. This debris was in places, especially 

 near the marginal walls, arranged in parallel 

 ridges trending with the axis of the valley; 

 and in the depressions between the ridges 

 were patches of snow and some small ponds. 

 Thus the moraine had a steep frontal slope, 

 but at the back merged with the ridged rock 

 debris which rose to still higher levels. There 

 were some depressions in the rock debris, 25 

 to 40 feet deep, which I took to be ice-block 

 holes. No bedrock was seen in the cirque 

 floor. 



During the recent meeting of the Geological 

 Society of America, Professor H. B. Patton, 

 of Boulder, Colorado, exhibited some photo- 

 graphs of the rock streams of Veta Mountain, 

 Colorado. One of these photographs showed 

 the high and steep front terminus of a rock 

 stream, and resembled very closely the front 

 slope of the supposed moraine in the San 

 Francisco cirque. Others of his pictures 

 showed the longitudinal parallel ridges which 

 characterize some rock streams, with bands of 

 snow lying in the hollows between the ridges, 

 just as was the case in the San Francisco 

 cirque at the time of my visit. If the con- 

 centric wave-like ridges pictured by Howe" 

 were present in the San Francisco deposits, I 

 did not notice them. 



I am inclined to believe that the features 

 which puzzled me at the time of my visit may 

 have been due to landslides or rock streams. 

 This does not mean that the depression in 

 which the features occur is not a glacial 

 cirque; nor that the moraines reported by At- 

 wood are not true moraines. It simply means 

 that I am not wholly satisfied with the evi- 

 dence of glaciation as reported by myseK. It 

 would seem that the possibility of a land- 



" " Landslides of the San Juan Mountains," U. 

 S. G. S. Professional Paper, No. 67. 



slide or rock stream origin for features ap- 

 parently due to glaciation must be carefully 

 considered, especially when glaciation in 

 doubtful localities is involved. 



D. W. Johnson 



THE TEACHING OF ELEMENTARY DYNAMICS IN THE 

 HIGH SCHOOL 



To THE Editor of Science: I have just 

 finished reading " The Teaching of Elemen- 

 tary Dynamics in the High School," by Wm. 

 Kent. I believe that Mr. Kent is right in most 

 respects except his last paragraph, where he 

 states : " It is high time they [teachers of 

 physics in the high schools] change their 

 methods and try the method that was success- 

 fully used fifty years ago." As one of the 

 physics teachers in secondary schools, I wish 

 to say that my own practise for many years 

 has not been materially different from that of 

 Mr. Kent and I wish to put in just a word for 

 the most of the physics teachers of my ac- 

 quaintance when I say that their practise and 

 that of Mr. Kent do not differ in any essential 

 particular. 



Again and again the discussion of the force 

 = mass X acceleration formula has come up 

 among groups of teachers and, in every case, 

 the verdict of the teachers has been that it 

 was not a formidable matter. Each knew a 

 way to teach it so that the pupil got the gist 

 of the matter even if he could not write a 

 text-book on it afterwards. And this is true 

 whether the instruction is given in English or 

 metric units. One is as easy as the other. 



Mr. Kent has evidently assumed from the 

 large amount of discussion on this question of 

 dynamics (kinetics) that there is something 

 radically wrong with the teaching of sec- 

 ondary school physics and that the chief cause 

 of any lack of efficiency is to be laid at the 

 door of that one little formula — f = ma. We 

 all may easily observe that those who are doing 

 the teaching are not the ones who are doing 

 the talking. It might be as readily discovered 

 that the great majority of teachers are going 

 ahead in a reasonably sensible way and are 

 teaching physics (and other subjects as well) 

 according to the dictates of common sense 



