HYDE: CAMAROPHORELLA. 37 
of death, although the latter are usually shattered in breaking open 
the hard sandy concretions in which they occur. The surfaces of the 
structures are usually coated with a thin film of pyrite which often, 
however, does not obscure any but the most delicate markings. In 
other cases the interior has been filled with sediment, since become 
extremely hard, and the fossils are preserved as internal molds from 
which the substance of the platforms, septa, etc., has been leached 
out, leaving them represented by clefts. 
The Burlington specimens are preserved only in a form similar to 
the latter, as internal molds in a moderately fine-grained siliceous 
sandstone. The surface has not been seen and what is known of the 
interior structure has been gained through a study of specimens in 
which the filling between the muscular platforms and the inner sur- 
face of the valves has been broken away, exposing the cavities or 
clefts which these platforms originally occupied. By the very nature 
of the specimens it would be difficult to learn anything of the deltitlial 
plates or spiral arms even though they were formerly a part of the 
shell. 
In the pedicle valve of both species there is a spondylium, concave 
inward, formed by the coalescence of the dental lamellae. In both 
species, apparently, it is supported throughout its length by a median 
septum. On either side of the spondylium a characteristic accessory 
supporting plate is developed in both to a greater or less extent. In 
the brachial valve there is a platform, convex inward, which takes its 
beginning beneath the hinge plate and extends for one third or more 
of the length of the valve. It is supported and divided into two parts 
by a median septum that penetrates it and extends for some distance 
beyond the inner surface of the platform. This septum also supports 
the well developed and characteristic hinge plate. It is on the com- 
plete identity of these three structures and the general similarity in 
shape that the statement of their congeneric nature rests. A descri} 
tion of the Sciotoville brachiopod follows. 
Detailed Description. 
External form and dimensions. — The species from Sciotoville 
shows a great amount of variation. In general the shells are meristel- 
loid in external form and moderately thick. The width is usually 
greater than the length but the opposite is true of a few indi\dduals. 
