294 
Aug. F. Foerste 
mon. The range of Proetus here is from 533 to 1002 feet below 
the lowest horizon at which Strophomena planumbona and Rhyn~ 
chotrema perlamellosa occur. The specimens of Cymatonota just 
mentioned occur in the upper part of this zone, between 533 and 
566 feet below the lowest Strophomena planumbona zone. Similar 
specimens of Cymatonota occur also 1699 feet below the lowest 
Strophomena planumbona horizon, in association with Trinucleus 
and Triarthrus, and some make their appearance as far up as 50 
and 105 feet below the lowest Strophomena planumbona horizon. 
Cymatonota of the same type occurs also at St. Hilaire; and 
about 12 miles east of Ottawa, at a road corner reached by going 
from Vars station three-quarters of a mile westward along the 
railroad, and then a mile northwestward along the country road. 
Among the species described by Ulrich, Cymatonota pholadis, 
as here described, most closely resembles Cymatonota recta, from 
the Fairmount member of the Maysville division of the Cincinna- 
tian, at Cincinnati, Ohio. A full description of Cymatonota recta, 
with notes on Cymatonota pholadis and C. parallela, is given in the 
Geology of Ohio, vol. vii, p. 662. 
27. Modiolodon poststriatus, sp. nov. 
{Plate I, Fig. 7) 
Cardinal margin slightly convex, joining the posterior outline, 
rather abruptly, at an angle of about 65 or 70 degrees. The basal 
margin diverges from the cardinal margin at an angle of about 15 
degrees, rounding rapidly into the posterior margin and into the 
anterior outline. The umbonal ridge is rather poorly defined in 
the specimen at hand. The anterior muscular area is strongly 
defined. Posteriorly, above the umbonal ridge, the shell is 
strongly marked by striae which are parallel to the posterior 
margin; of these striae there are about 9 in a length of 5 mm. 
Elsewhere on the shell there are only faint indications of concen- 
tric striae. 
Length 35 mm., height posteriorly 20 mm., height at beak 14 
mm., extension of shell anterior to beak about 3 or 4 mm. 
Locality. One mile west of Vars, along the railroad, and then 
half a mile northward along the road, associated in the same slab 
with Catazyga headi; collected in 1912 by Aug. F. Foerste. Pre- 
