306 
Aug. F. Foerste 
the Triarthrus hecki horizon, immediately overlying the River 
quarry beds, opposite Cincinnati, was well known and the same hori- 
zon, is typically exposed at Point Pleasant. Below this Triarthrus 
hecki horizon, both at Cincinnati and at Point Pleasant, occurred 
coarse-grained layers of limestone containing apparently the same 
species of Trinucleus concentricus as that occurring in the strata over- 
lying the Triarthrus hecki horizon. At Point Pleasant there were hill 
quarry beds as well as river quarry beds. The former included chiefly 
the strata extending between 75 and 115 feet above the water level, 
and the latter extended along the immediate edge of the river and 
were worked chiefly at low water, although locally rising to about 
15 feet above the water’s edge. This explains Orton’s statements 
in his original definition of the Point Pleasant beds (Ohio Geol. 1, 
1872, p. 370): 
the river quarries in the central portions of Clermont 
county, which lie a dozen miles south of Cincinnati, disclose rocks 
that underlie by at least 50 feet the lowest beds at Cincinnati. The 
locality at which these lowest rocks of the State present the best 
exposures and clearest section is Point Pleasant, and this division 
can accordingly be named the Point Pleasant beds. Its boundaries 
have been already assigned by implication; these beds beginning at 
low water mark at Cincinnati, and descending until they include 
the lowest rocks exposed in the State.” 
17. Lingula vanhornei, Miller 
{Plate III, Fig. 6, Plate IV, Fig. 5A, B) 
1875. Lingula vanhornei Miller, Cincinnati Quart. Jour. Sci., 2, p. 9, Fig. 1 
The type of Lingula vanhornei, numbered 8865, in the Faber 
collection at Chicago University, is an entire shell, partly exfoliated. 
The illustration accompanying the original description represents 
the pedicel valve, and this valve is illustrated also in the present 
bulletin. 
The species appears more closely related to Lingula procteri 
Ulrich, as illustrated by Hall and Clarke (Pal. New York, 8, pt. 
1, pi. 1, figs. 5, 6), than to the group of species typified by Lingula 
cincinnatiensis, of which Lingula iowensis is a member. In Lingula 
iowensis, the brachial valve is characterized by a bold, sharp median 
septum, terminating abruptly a considerable distance anterior to 
the concrete laterals, of Hall and Clarke. No such conspicuous 
