430 MEMOIRS OF THE CARNEGIE JIUSEUM 



in the formerly glaciated area, for these are due to Postglacial expansion. But 

 looking upon the localities south of the terminal moraine (PI. XLII, Fig. 3) we see 

 that only a few are known for C. pi'ojnnquus, and these are all in southern Indiana 

 (Prown, Monroe, and Green Counties),*' and belong very likely to the old Lower 

 Ohio drainage, hut in the region where it comes into, contact with the suj^posed Old 

 Miami River (or possibly some other river flowing north in the State of Indiana). 

 Since we have reason to believe (Orlmann, 19056, p. 114) that the center of ra<lia- 

 tion of the subgenus Faxoiiins, to which the propinquus-group belongs, is in the 

 centi-al basin formed by the thi'ee great rivers (Missouri, Mississippi, and C)hio), ('. 

 prop'hiqavs distinctly points toward this center, of which southern Indiana forms 

 part. This is the more interesting since we see that it is the most primitive species 

 of the jirojiiiiijtiux-gvou]) which most closely approaches the original center. In 

 Preglacial times ('. prujiliiquns belonged to the northeastern extremity of the old 

 Ohio drainage (Lower ( )hio), and in tliis region there apparently was a chance for 

 it to cmss over the continental divide into the Atlantic (St. fjawrence) drainage. 

 If however, the Erigan River drained to the Mississippi, the presence of this 

 species in the Lowej- (_)hio and in the lower part of the Erigan River is more easily 

 accounted fnv Ijy direct communication of the waters. 



Taking up tlie distribution of ('. projiinqiins sanJxrrni, we observe that until 

 recently oidy one locality was known to the south of the di'ift, namely, the type 

 locality in Carter County, Kentucky, which is undoubtedly in the drainage of the 

 Old Kanawlia River. In addition, I have discovered a number of localities in 

 eastern Ohio (< 'arroll, Harrison, and Stark Counties), and in northern West Virginia, 

 wbich l)elong to the same drainage (Newark River and Marietta River, tributaries 

 of the ( )ld Kanawha), which are also outside of the glaciated area (at Canton, 

 Stark ( 'ounty, ( )hio, close to the edge of the drift). 



The chorological facts about the disti-ilnition of ('. jiropinqtiv^ and C. jiroprnqiius 

 sanhorni are very meager, and not at all .satisfactory; but as far as our present 

 knowledge goes, all known localities of C. propiiKpnix sdiilmnii, outside of the drift, 

 are in the drainage of the Old Kanawha, while none of the known localities of ('. 

 propiiiqnu^ are in this drainage, but are situated to the west of it. Now, this 

 mutual relation between distribution and Preglacial drainage becomes more evident 

 when we look upon ('. oltsrnrn.'^, the distribution of which 1 have studied more 

 closely. 



*'They are close to tlie southern etifie of tlie drift, ami it is a little doubtful wlietlier they are inside or outside of 

 it. Disregarding the Ulinoisan drift, they are surely outside of the Postillinoisan glaciation, as is also a loaility in 

 Franklin County, Ind. 



