ART. 6. AN OVERLOOKED SPECIES OF MUSK TURTLE—STEJNEGER. 3 
But what business has S. minor in the upper Tennessee River 
when it does not occur in the lower reaches of that river nor else- 
where in the Mississippi River drainage? Two articles in Science 
(vol. 12, new series, July 27, 1900) afford a very satisfactory answer 
to this question. The first one,? by Hayes and Campbell, gives a 
condensed account of their demonstration, based on purely physio- 
graphic evidence, that the Tennessee River some time in late Miocene 
was captured by the Mississippi drainage, and that before that time 
the upper Tennessee River flowed into the Alabama River system 
through the Coosa River. In the second article,’ Mr. Charles T. 
Simpson showed that he had come to the identical conclusion on the 
basis of purely biologic evidence, namely the distribution of certain 
pearl mussels which are specifically identical in the two river 
systems. 
It is then evident that at the time when the Tennessee River flowed 
directly southward from Chattanooga, and not toward the west as 
now, emptying into the Mississippi embayment far to the east of the 
mouth of the Mississippi River, the S. minor inhabited the upper 
drainage of eastern Alabama and western Georgia including the Appa- 
lachian Valley at least as far north as east central Tennessee. 
We have thus not only a satisfactory explanation of the occurence 
of S. minor in the upper Tennessee, but the evidence is pretty con- 
clusive that this species existed in its present form as early as the 
late Miocene, and that the genus Siernotherus consequently is much 
older. The contrary opinion, namely, that the Kinosternons are of 
very recent origin, because no fossil Kinosternid has been recorded, 
consequently falls to the ground and proves how dangerous it is to 
base any conclusions upon the negative fact of no paleontological 
record. Moreover, the lacking paleontological evidence has recently 
been furnished by the find of a fossil species of Kinosternon in 
Arizona, collected by Dr. J. W. Gidley and described and figured by 
Mr. C. W. Gilmore, both of the National Museum.' 
2The relation of biology to physiography, pp. 131-133. 
3On the evidence of the Unionidae regarding the former courses of the Tennessee and other southern 
rivers, pp. 133-136. 
4Proc. U. S. Nat. Mus., vol. 62, art. 5, 1923, pp. 1-8, pls. 1-5. 
