E— GEOGRAPHY 



107 



culture-complex in the State of Kentucky. Everyone has heard of the 

 Blue-Grass Country around Lexington, and its association with horses 

 and racing. It is rather sharply marked off from neighbouring areas, and 

 its site is exactly determined by the geological structure (Fig. 3). The 

 Blue Grass Region is an * Eroded Dome ' much like the Weald. Here 

 the fertile Trenton formation (of upper Ordovician age) is surrounded by 

 rather sterile Carboniferous rocks. A similar eroded dome surrounds 



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Fig. 2.— The Wool Industry in Sussex about 1350, determined by the Chalk 

 Cuesta of the South Downs (based on R. A. Pelham). The black squares 

 represent from 500 to 1,000 sheep in a parish. 



Fig. 3. — Correlations between Geology (Eroded Domes) and Horse-breeding in 

 U.S.A. Figures indicate approximately ' Horses per square mile.' 



Nashville to the south. In Fig. 3, I show the close correlation between 

 the Ordovician beds and the density of horses in these regions of Kentucky 

 and Tennessee (Finch and Baker 1917). Such comparisons show how 

 the geographer can help the historian to elucidate culture in almost any 

 district in which he may be interested. 



Few students seem to have made use of graphical methods in investi- 

 gating their historical problems. These are, of course, the chief charac- 

 teristic of geographical research. Especially is this true in regard to the 

 use oihopleihs (lines of equal abundance), which can be applied to cultural 



