January 3, 1908] 



SCIENCE 



31 



says the specimen consisted of " ten consecu- 

 tive vertebrse and their appendages," and this 

 is the number of vertebrae figured on the plate. 

 Nowhere is D. articulatus designated as a new 

 species and the original description applies 

 exactly to the figures there given. 



Cope's ability to shift names is well known 

 to those who are accustomed to deal with 

 subjects treated by him, but usually such 

 shifted names were detected, either by Cope 

 or others. This appears not to be the case 

 with Dissorophus and, so far as I can learn, 

 the correction has never been made. Dis- 

 sorophus muUicincius Cope is the only spe- 

 cies of that genus which is valid and it is de- 

 sirable that the synonymy of D. articulatus 

 with the first described D. multicinctus should 

 be established before the mistake goes further 

 into the literature. Roy L. Moodie 



The University of Chicago, 

 November 14, 1907 



CURRENT NOTES ON LAND FORMS 



THE PENEPLAIN OF NOETH CENTRAL WISCONSIN 



The peneplain of north central Wisconsin 

 has been recently described with rare skill by 

 S. Weidman in a state survey report (Chap. 

 XII., pp. 575-631, in " Geology of North Cen- 

 tral Wisconsin," Bull. XVI., Wise. Geol. and 

 N. H. Surv., 1907). The teachers of the state 

 and geographers in general will here find excel- 

 lent account and illustration of the still undis- 

 sected parts of the peneplain, of the well- 

 defined, though small, monadnocks that rise 

 above it, and of the valleys that have been 

 eroded beneath it; they will find also a well- 

 considered and lucid discussion of the origin of 

 these features. The once continuous upland 

 is ascribed with good reason to the destruction 

 of ancient mountains of disordered and gen- 

 erally resistant rocks in an almost complete 

 pre-Cambrian cycle of subaerial erosion. The 

 submergence of the resulting peneplain, its 

 burial beneath an unconformable cover of 

 paleozoic strata, the elevation of the region 

 with the resultant removal of the covering 

 strata and resurrection of the buried pene- 

 plain, and the dissection of the peneplain by 

 superposed rivers are all clearly set forth. 



The upland rises from 1,000 feet at its south- 

 ern border to 1,500 feet at the northern part of 

 the area. As the rivers are followed south- 

 ward, there is a gradual transition from well- 

 enclosed valleys, 200 or 300 feet deep, floored 

 and sided with disordered rocks, through shal- 

 lower valleys, floored with disordered rocks but 

 sided with stratifled rocks, to open valleys, 

 floored and sided with stratified rocks. There 

 is a corresponding passage from higher, more 

 northern uplands of disordered rocks, through 

 somewhat lower uplands, patched over with 

 scattered remnants of the once more extensive 

 cover of stratified rocks, to the lower ground 

 of the still remaining, continuous stratified 

 cover. All these features are so well presented 

 that they may be accepted as standard ac- 

 counts of typical physiographic features. If 

 a hesitating geographer is still to be found, 

 unconvinced of the desirability of replacing 

 older empirical methods by newer explanatory 

 methods in the description of land forms, let 

 him read this essay. 



The attention of others engaged upon phys- 

 iographic reports for state surveys may well 

 be directed not only to the general plan of 

 this report, but particularly to four helpful 

 block diagrams (pi. 68-71), which promptly 

 and concisely set forth the essentials of the 

 story to be told, so that its details may after- 

 wards be apprehended in proper relation to the 

 more general features. The chapters on 

 glacial and alluvial deposits also contain geo- 

 graphical material. One of the very few 

 points on which Weidman's form of statement 

 might be changed to advantage is that con- 

 cerning the adjustment of rivers. It is said: 

 " Under normal conditions, streams . . . tend, 

 not only to flow in nearly direct courses, but 

 also to avoid the harder rocks, thus seeking to 

 establish their courses upon the softer forma- 

 tions and to move along lines of least resist- 

 ance " (p. 616). This might give the impres- 

 sion that the establishment of stream courses 

 along belts of weak rocks is accomplished by 

 the preexistent streams themselves, as an ac- 

 tive, almost intentional process. The quoted 

 phrase might be changed to read : " Streams of 

 early origin are often led to avoid the harder 

 rocks by the later development of subsequent 



