CHECKERBOARD TOPOGRAPHY 131 



"At many places on the west coast the land is cut up in the most striking 

 manner into diamond-shaped areas by the coastline, the fjords and 'sounds' 

 connected with it, or, if these are filled with sand, by the 'Eide.' Whoever has 

 wandered through this region has required no map in order to recognize this 

 impress upon the relief or the physiography of the landscape, since each sec- 

 tion of the mountains stands cut off at an angle and separated from neighbor- 

 ing sections by a visible sunken area, almost after the manner of a wall with 

 embrasures cut out." 



Thus if one could view the surface of the country from a series of suffi- 

 ciently high points, say from a moving balloon or from an aeroplane, 

 there would be displayed a repeating pattern in the relief — the surface 

 would be seen to be subdivided into similar compartments, as is a closely 

 paneled wainscot. The term checl-erhoard topography was used by the 

 writer in 1901 to describe such a repetition of a simple and regular diaper 

 pattern in the relief of a district (see plate 9).^ For the reasons already 

 given, such patterns are apt to be especially distinct in high latitudes, 

 where vegetable cover is scanty and where frost work is the dominant 

 weathering process. On the basis of earlier studies, also, it may be 

 stated that the characteristic relief pattern is one which not only repeats 

 itself, but the same design is repeated in units of larger scale because of 

 the grouping to form blocks of similar shape but of higher orders of mag- 

 nitude. These, in turn, repeat in higher and still higher orders,^ A 

 similar grouping into larger units is brought out by Kjerulf's map of the 

 larger lines in the relief of Norway (see figure 7). 



THE PRIMARY UNIT OF THE SUBDIVISION 



The lowest order of unit pattern may be conceived to be the individual 

 joint block limited by consecutive joint planes in each of two or more 

 series. Under exceptionally favorable circumstances, where there is no 

 vegetable cover, these units may even appear in the relief of the country, 

 because each is the locus of effective frost action. In western Greenland 

 an illustration is found, and an embrasure-like notching of the coastline 

 is also to be observed (see figure 8).'^ A grouping of the smallest units 

 into blocks of six or eight thus appears to be indicated by the shoreline. 

 Still larger groups are indicated upon a smaller scale map of the same 



5 The Newark system of the Pomperaug Valley. Twenty-first Annual Report of the 

 U. S. Geological Survey, pt. iii, 1001, p. 150. See also Bulletin of the Geological Society 

 of America, vol. 15, 1904, p. 500, pi. 47. 



•Twenty-first Annual Report of the U. S. Geological Survey, pt. iii, 1901, pp. 104-121, 

 pis. Ix-xi, figs. 43-46 ; Bulletin of the Geological Society of America, vol. 15, 1904, pp. 

 500-506 ; Comptes Rendus 8me Cong. G^ogr. Intern., 1906, pp. 193-202. 



'A. Kornerup : Geologiska lagttagelser fra Vestkysten af Gr5nland (66° 55'-68'' 15' 

 N, Br.), Medd. om Gronl., vol. 2, 1879, pi. vili ; resume on pp. 180-181. 



