242 



characteristically valley-like, and the topography merely un- 

 dulating or hilly. (The railroad goes through two tunnels in 

 Montgomery County, Virginia, one in Pulaski County, and one 

 in Hamilton County, Tennessee.) 



Rock outcrops are very irregularly distributed along the route, 

 being abundant in some parts and practically wanting in others. 

 In some places, where limestone predominates, the drainage is 

 largely subterranean, and lime-sinks are frequent; but generally 

 there are streams of various sizes in sight. The more level areas 

 are mostly cultivated or pastured, and the hilly and rocky places 

 pastured or wooded. Pastures are more prevalent northward, 

 here as in several other regions. 



At daybreak on April 23, 1912, I was just passing Roanoke, 

 Va., going south westward, and by nightfall, 133^ hours later, I 

 had reached Chattanooga, Tenn., 392 miles away. I remained 

 on the same train as far as Fort Payne, Ala., passing through the 

 northwesternmost county of Georgia for about 25 miles after 

 dark; and the next day I continued my journey by daylight to 

 the southwestern end of the valley and beyond. (The Alabama 

 end of it has recently been described in my geographical report 

 on the economic botany of Alabama.*) 



In traveling lengthwise of the valley one does not cross any 

 natural boundaries that have much geographical significance, but 

 in order to bring out some differences in plant distribution due 

 to latitude, etc., the route will be divided arbitrarily into four 

 approximately equal parts. 



In the following table the plants identified from the train 

 two or more times between Roanoke and Woodstock are divided 

 into trees, shrubs and herbs, and four numbers are prefixed to 

 each species. The first denotes the number of times the plant 

 was seen between Roanoke and Bristol, 150 miles, the second is 

 for Bristol to Knoxville, 131 miles, the third for Knoxville to 

 Chattanooga, iii miles, and the fourth for Fort Payne to Wood- 

 stock, 120 miles. 



For those who may wish to correlate distribution with political 

 boundaries it wall be convenient to remember that the first 



* Geol. Surv. Ala., Monog. 8: 58-63. June, 1913. 



