306 ORTMANN—CORRELATION OF SHAPE AND 
Allegheny River. 
IN AER OTA, cima cis oamoictotehe safekeraere I 52 52 52 lens 
Godiirey “.) ee rrusce cee oe hate ne I 5I 5I 51 lens 
Crooked Creek. 
RGSSEOIUL Bee rome Cercle etoeveioe nents 12 590 48 52 lens 
Creeksidei gy. cc jaca se dieninn Mtavarectere 5 oT 48 50 lens 
The sudden decrease of obesity from the Monongahela to West 
Fork River is clearly due to the absence of material from a long 
stretch in the Monongahela. Also in the Allegheny the change is 
rather abrupt, due to scarcity of material. The gradual transition 
of the two forms is, however, quite evident in the Beaver-drainage. 
Loc. No. Max. Min. Av. 
Beaver River. 
\WWeniahoybhanh” Aoawlosmineita cooobcen dace 14 64 49 53 lens (subr.) 
Shenango River. 
arbor Sinidoemeecesce cere tas 3 56 50 53 lens 
slag ki sher ern tia aes piston 2 58 49 53.5 lens 
Glarksyvillew yeah stoetuscict eee clones 7 54 48 SI lens 
Also in Elk River in West Virginia this is seen. 
Loe. No. Max. Min. Av. 
Elk River. : 
Sieltonee se cree ein cnterek nen score cess I 67 67 67 subr, 
Cl aigmeeriaiocictinci& crleistere Heiaeucvers 2 62 60 61 subr. 
(GasSawaye doscuiiiet cic e sae oer of 70 56 61 subr. (lens) 
SiilOn Wane te laoe wee cee 9 65 53 58 lens (subr.) 
Some material from the Little Kanawha also fits into the scheme, 
but it should be pointed out that the locality on Hughes River, 
although not quite so far upstream as the others, surely is in the 
smaller stream. 
Loc. No. Max. Min. Av. 
Little Kanawha River. 
Gramtsvillletencr ae cree tetetos me craioree 2 68 50 63.5 subr. (lens) 
Bisetrsvalll Circ eiye rarssatere eee eke cates 5 50 50 53 lens 
North Fork Hughes River. 
Contiwallist..accmiancohinieecocee owe I 50 50 50 lens 
GROUP OF OBOVARIA SUBROTUNDA IN THE UPPER TENNESSEE. 
In the uppermost Tennessee drainage, Obovaria subrotunda is 
extremely rare; above Knoxville, it does not go anywhere into the 
