Anculosae; of THe Alabama River Drainage 7 



as an extension of the Sequatchie River or as a small stream that now is 

 a northern branch of the river. A question may be raised as to whether 

 the valley containing both the Sequatchie and this northern reach of the 

 Black Warrior ever was occupied by a single stream flowing its full length. 

 It may be that in the Cretaceous the Tombigbee was not in existence at all. 

 In every h'klihood the Anculosae reached the three streams, Cahaba, Black 

 Warrior and Tombigbee, from the Coosa River after the elevation of the 

 continent and the linking of all these rivers with the Alabama. 



Character of Alabama Streams 



The Coosa is said to have the most diversified molluscan life of any 

 stream in the world. It has long been a classical collecting stream. Yet 

 not until iNIr. Smith undertook the labor was the collecting carried out in 

 any systematic way. Concerning the reasons for the extensive animal popu- 

 lation, j\Ir. Smith — so far as I can discover — has ventured to say nothing. 

 But of the character of the Coosa and other Alabama streams, there occur 

 many illuminating passages in his correspondence with Dr. Walker. Some 

 of these are here printed in their chronological order. 



From Wetumpka, he wrote toward the end of 1901 : 



"There is an island half a mile up the river, and we tried vainly to reach 

 it for a long time, the water was too deep and swift. After awhile I man- 

 a!ged to get a boat, and since then most of my collecting has been on the 

 island. It is rocky and intersected by a number of small water channels, 

 with numerous back-water pools. This island has turned out an astonish- 

 ing number of species. ^Many of the forms are extremely rare and local. 

 One pool is crowded with small species, some not over one-half inch, and 

 it is about the only place in which I have found small ones at all." 



Writing from Gadsden in October, 1904, ]\Ir. Smith said : 



"From Rome to Gadsden we found a constant succession of shoals, 

 either along the shores or forming islands in the river. I think that the 

 river shells are substantially the same down to the mouth of the Chat- 

 tooga River. At first I thought there was a gradual change, but I found 

 that a recurrence of the same conditions brought the same species. Below 

 the Chattooga there are few shoals for ten or twelve miles ; then a succession 

 of rock and shingle shoals clear down to Gadsden ; and on these we found 

 a good many forms not seen above. I think, however, that this is only be- 

 cause the fauna gets richer; most of the species seen above persist as far 

 as Gadsden." 



In November of the same year he was at Riverside, writing : 



"The Coosa below Gadsden is at first like the upper reaches. At the 

 upper end of Minnesota Bend there are limestone rocks and shoals. Fol- 

 lowing this is a long stretch, eight or ten miles, in which the river is broad 

 and lake-like with muddy bottom and low shores. I should think such 

 reaches would be a pretty effectual bar to the migration of rock loving 



