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of brachiopods, and these are in many places numerous in the accompany- 
ing clay strata; from these clay strata the shells weather out perfectly. 
This note concerns itself with two species of these brachiopods—Orthis 
biforata and Orthis occidentalis. The first of these has its hinge line 
sometimes greatly prolonged, asin Vig. (1). Every gradation in this respect 
is to be found.as shown in Figs. (2), (83), (4) and (5). Specimens like Fig. 
(1) are to be found in the uppermost strata, and those with the hinge line 
less and less prolonged are found in lower and lower strata until finally 
in the lowest strata those without any prolongation—Iig. (5)—are to be 
found. The matter of interest is that the development of the hinge line 
went forward during the entire time of the formation of these rocks; its 
development is roughly in proportion to the altitude. 
Forms like Figs. 4 and 5 continued to survive and are found at all 
horizons, but forms like Fig. 1 are not to be found at the lower horizons. 
A similar change is to be noticed in Orthis occidentalis. Typical speci- 
mens of this species found at a low horizon have a channel along the 
middle line from the umbo to the anterior margin; see Fig. 6. But as one 
searches in higher and higher strata he finds the. channel dying out and 
a ridge taking its place, until in the highest strata the typical species is 
displaced by its variety, Orthis sinuata, Fig. 7. 
NoTES ON THE DISTRIBUTION OF THE KNOBSTONE GROUP IN INDIANA. 
By J. F. Newsom anp J. A. PRICE. 
| Abstract.] 
The series of shales and sandstones in Indiana known as the ‘‘Knob- 
stone” has been grouped to itself principally because of its lithological 
characters. Because of its stratigraphical position with regard to the 
Lower Carboniferous limestones it has been regarded, in part at least, as 
the equivalent of the Kinderhook group of [linois. 
On Gorby’s geological map of Indiana, of 1893, the Knobstone area 
is represented as extending as far northward as Honey Creek Township, 
in White County. 
Field work done by the Indiana University Geological Survey in 1897 
shows that the area underlain by the Knobstone does not extend so far 
north of Putnam County as has been hitherto suspected. It also seems 
19—ScreNCcE. 
