NAIADES OF MISSOURI ^$ 



very pleasant and extensive cocrespondence with these last three 

 named gentlemen many problems have been solved and all novel- 

 ties and changes have passed through their censorship. 



In order to elucidate the references in the text made to the 

 physiography and geography an excerpt of the geographic distri- 

 bution and also a tabulated Account of the Mussel Faunae of 

 Missouri are given here, although, when it is possible to secure 

 the desired data, it is the intention of the author to give a detailed 

 account of the zoogeography of the Naiades of Missouri and adjacent 

 territory in relation to the restoration of the ancient geographic condi- 

 tions of Central Mississippi Valley. 



In this connection the hydrography of the vState may also be 

 given for the sake of clearness in the use of the text. The drainage 

 to the Mississippi is mostly through the Missouri River which 

 flows entirely across the State just above the central line, and. 

 because of the loess soil held in suspension, together with its 

 shifting sand bars and mud beds, it forms "a great faunal 

 harrier^ Hence we may account for such a distinct mussel fauna 

 north of the Missouri (known as "Old Muddy") from that south 

 of it. The depauperization of mussel life is remarkable as noted 

 in this river, together with that of the Mississippi from the mouth 

 of the Missouri to a point below the southern boundary line of 

 the State. The chief river basins of North Missouri belonging 

 directly to this faunal barrier are the Chariton, the Grand, the 

 Platte, the Nodaway and other minor ones of the Northwest. 

 A chain of lakes, formed by the changing of the Missouri River 

 channel into "ox-bow cut-offs," are found mostly in the north- 

 western part of the State along the Missouri in its eastern and 

 northern flood-plains. The largest river basins draining into the 

 Missouri River from the south are the Osage, Gasconade and 

 Black-water. The most important one which drains directly into 

 the Mississippi from this vState is the Meramec. The chief basins 

 found on the south slope of the Ozarks are the White, Black and 

 St. Francis Rivers which are drained into the Mississippi through 

 Arkansas. South-west Missouri drains into the Mississippi River 

 partly and directly through the Neosho. 



The following is a Classified Account, (although apparently 

 contrary to the geologic facts, yet self-explanatory), showing the 

 distinct mussel faunae of the State that coincide with the diflferent 



