HARPER: TRIP ON WARRIOR AND TOMBIGBEE RIVERS 111 
quently. The bars of sand and gravel which give rise to shoals 
have been mentioned above. 
In Choctaw, Clarke, and Washington counties on the last two 
days of the trip we got frequent glimpses of the “ mountains,” 
which are a characteristic feature of this part of Alabama * and 
adjacent Mississippi, but are almost unknown to botanists and 
geographers. These are high rocky ridges, mostly of the buhr- 
stone (Middle Eocene) formation, extending in a general north- 
= 
FIGURE I. Mt. Ararat (near the center) and McCarthy’s Blaff, Choctaw County, 
Alabama, looking downstream from the boat, October 15, 1908. 
west-southeast direction. Ina few places where the river impinges 
directly against them they form bluffs over 200 feet high, which 
s ‘doing pretty well” for the coastal plain. A distant view of 
one of them is subjoined. A few plants which grow on them are 
mentioned in the geological reports cited, and some others will be 
discussed in the latter part of this paper. 
Four divisions of the Cretaceous strata are represented in 
western Alabama, namely, the Tuscaloosa, Eutaw, Selma Chalk 
or Rotten Limestone, and Ripley. These are quite easily recog- 
nized along the river by their different appearance or lithological 
*See seuith, cae Census U. S. 6: 55 (line 11), 143-145 Sa5re mare n}. 
1884; U. S. Geol. Surv. Bull. 43: 35-42. 1887; Geol. of Coastal Plai Ala, 
620-622, 630, a 634, 640-641, 645-647. 1894; Mohr, Contr. ie S. Nat. an 
6: 107. I901 
