PORTION OF THE SCHUYLKILL COAL-FIELD. 83 



interior structure, the grouping of its mountain masses, the incli- 

 nations, bearing, direction, contortions and dislocations of the 

 strata into which those formations and masses are subdivided, to 

 be exhibited in a simple, yet very striking and appropriate man- 

 ner. With the addition of superficial coloring, the pictorial char- 

 acter of the region represented, can be as accurately depicted as 

 in a highly finished landscape. Perhaps even more so, inasmuch 

 as the positions of all surrounding objects, and of all accessory 

 details, are jiefined with geognostic accuracy in the one case, 

 rather than imperfectly traced in the other, however experienced 

 may be the hand and the eye of the artist. The interesting and 

 accurate effect incidental to a picture, thus formed in relief, is ap- 

 parent enough when the observer brings his eye to the level of 

 any point whatever on the model ; — the summit of a mountain, 

 the point of a bluff, or the curve of a river, for instance, — from 

 whence all that he needs in obtaining at ease and convenience a 

 view of the surrounding scenery, is accomplished. 



For topographical observations, for rapid reconnoissances, for 

 tracing routes for rail roads, for canals, or for ordinary roads and 

 communications, the model system presents facilities for num- 

 berless practical purposes, and may be the means of saving a 

 great deal of preliminary labor and expense, on such occasions, 

 in a mountainous or forest district. 



In all such regions, it is common to adopt as the best, because 

 they are the most natural and the most permanent, lines of de- 

 marcation, the elevated chains, the elongated ridges, the ranges 

 of highlands or platforms which divide the sources of rivers and 

 influence the descent of drainage ; or to constitute the rivers 

 themselves, as they flow between these ranges, the boundaries of 

 local and territorial jurisdictions. AH of these are particularly 

 and necessarily prominent features in a model ; and these, the 

 most sublime and most imperishable monuments in aU countries, 

 have with propriety been selected as the most fitting for such 

 conventional purposes. Had a model, however roughly con- 

 structed, been in existence to illustrate the physical geography of 

 what is termed " the disputed territory " in the northeast, half a 

 century of embarrassment and conflicting opinions, and local dif- 

 ficulties, might have been saved to the interested parties. It is 



