June 5, 1908] 



SCIENCE 



893 



The Mapping of Landforms: Mr. F. E. 



Matthes. 



An attempt is offered in this paper to place 

 tlie mapping of landforms on a more rational 

 basis than has obtained hitherto, and to estab- 

 lish such fundamental principles as may serve 

 to guide the topographer in the judicious 

 representation of the relief on reduced scales, 

 and thus lead to gTeater uniformity and con- 

 sistency of interpretation. 



In the first place a thoroughgoing analysis 

 and classification of landforms seems neces- 

 sary for a general groundwork. 



Beginning with the continent as the largest 

 unit landmass, several primary subdivisions of 

 a comprehensive nature — physiographic prov- 

 inces — may first be blocked out. Each of 

 these again may be divided into smaller tracts 

 or physiographic regions, each of them a dis- 

 tinct physiographic unit. Thus the entire 

 Appalachian complex, from the New England 

 ranges down to Alabama, may be spoken of 

 as a " province " ; each of its subdivisions, 

 like the Alleghany Plateau, the Eidge-and- 

 Valley Belt, or the Piedmont Plateau, on the 

 other hand, as a " region." 



The character of the relief of a " region " 

 varies, as a rule, considerably from one part to 

 another, and further subdivision into topo- 

 graphic districts suggests itself; each district 

 having a distinct and fairly uniform topo- 

 graphic character of its own. " Topographic 

 character " as a specific term, therefore will 

 be used as referring properly to topographic 

 districts. Analyzing now what determines 

 topographic character, we find that three fac- 

 tors enter into it: (1) the vertical measure 

 of the relief, (2) the types of landforms repre- 

 sented, (3) the disposition or manner of as- 

 semblage of the topographic units. 



For the topographer's purpose it is helpful 

 to resolve the landscape into component land- 

 masses each of which may be considered by 

 itself as a topographic entity or unit. Thus 

 each mountain, spur, ridge, hill, mesa, terrace, 

 cliff, fan, fiood-plane, dnne, sink, moraine, 

 drumlin, cirque, cone, etc., constitutes 'i, topo- 

 graphic unit. Obviously there are as many 

 different kinds of topographic units as there 

 are types of landforms. Not only, but the 



units of a given type frequently occur, asso- 

 ciated in different sizes, and are therefore 

 capable of being further classed by order of 

 magnitude. Thus an entire mountain range, 

 a single mountain on the same, a master spur 

 of the mountain, a small spur of the master 

 spur, a spurlet of the smaU. spur, etc., consti- 

 tute units of successively lower orders of mag- 

 nitude, yet all belonging to the same type of 

 stream-carved landforms. The topographic 

 character of a given district then depends 

 largely on the kinds and sizes of topographic 

 units represented within its compass. Con- 

 tiguous districts, however, characterized by 

 the same topographic types and the same 

 height of relief, may yet differ conspicuously 

 in topographic character because of differences 

 in the disposition of the units. A third factor 

 must therefore be taken into account, namely, 

 the disposition, grouping or manner of as- 

 semblage of the topographic units. This con- 

 cept is covered for stream-dissected districts, 

 by the term " topographic texture," and the 

 same may perhaps with propriety be extended 

 to others not composed of units of stream- 

 dissection, so that it will serve to designate 

 the manner of assemblage of topographic units 

 of all types. Thus a number of different 

 textures may be recognized, such as coarse, 

 fine, uniform, irregular, graded, homogeneous, 

 heterogeneous, simple, intricate, linear, trend- 

 less, radial, peripheral, etc. 



Starting with this classification of land- 

 forms and this concept of topographic char- 

 acter as a basis, it is now in order to proceed 

 with the formulating of criteria for the use 

 of the topographic delineator. 



From the foregoing it follows at once that 

 a map which aims to give an expressive repre- 

 sentation of the relief must satisfy three con- 

 ditions: (1) it must correctly indicate the 

 measure of the relief; (2) it must faithfully 

 delineate the true character, shape and size of 

 each topographic unit; (3) it must be reliable 

 as to the relative position and orientation of 

 the units, that is, it must show the texture 

 characteristic of each district. 



These rules apply to all topographic maps, 

 whatever the scale or the nature of the carto- 

 graphic device used for the representation of 



