28 W. M. DAVIS 



certified procedure, for it is presented as the normal sequence of 

 change not only in my own earlier published statement of such a 

 cycle, which Penck now criticizes, but also in his own exposition of 

 the cycle scheme in his chapter on "Die Erdoberflache " in the 

 fifth edition of Scobel's Geographisches Handbuch (1908) above 

 referred to; he there explained the successive stages of a cycle of 

 erosion, with its organic terms, young, mature, and old and with its 

 sharpened ridges afterward rounded, as a matter of common and 

 generally accepted physiographic knowledge, for which he very 

 properly accepted the responsibility while enjoying the profit, thus 

 making a marked and very advantageous forward step from his 

 treatment of the same chapter in the second edition of 1895. Flat 

 inter-valley uplands, sharp-crested ridges, and rounded or subdued 

 ridges are there described very expHcitly as constituting the normal 

 sequence of forms (Sc. 144). Not only so, the first ideal cycle in 

 the "Gipfelflur" essay, in which a lowland of erosion is assumed 

 as the antecedent form, presents the same normal sequence (264). 

 Hence one cannot help wondering why, if it be thought necessary 

 to assert that the special Alpine sequence stands in opposition to an 

 earlier deduced sequence, Penck's own earHer scheme, as well as that 

 of one of his contemporaries, is not instanced. But in reality no 

 such assertion is necessary, because the two sequences do not stand in 

 opposition to each other. The impHcation of opposition is irrelevant. 

 Independence of upheaval and erosion. — In certain other respects 

 also Penck's new views are presented as corrections of view previ- 

 ously announced; and in all these cases, as well as one instanced 

 above, the previous views that he selects for correction are mine. 

 This does me entirely too much honor, for the views of mine that 

 he selects for correction are dupHcated in the pubHshed statements 

 of his own earlier views. Had his earlier views been pubHshed 

 merely as quotations from my writings, his present responsibility 

 would have been less ; but they were not; they were very properly 

 pubhshed as his own views and that being the case, his own earlier 

 statements should receive correction along with mine, if correction 

 is really called for. But as a matter of fact correction is not called 

 for. The views that Penck now announces are merely extensions, 

 not corrections of earlier views that both of us have held. 



