156 GEOLOGICAL SURVEY OF THE TERRITORIES. 
This form is characterized by the lateral compression of the lower 
portion of the corallum, a feature not possessed by any other Zaphrentis 
so far as I am aware. 
Position and locality—Burlington limestone division of the Subear- 
boniferous series, Burlington, Iowa, its position being at the base of 
that division, in strata which contain several invertebrate species which 
are common to the Kinderhook strata beneath. 
ZAPHRENTIS CALCEOLA White & Whitfield. 
Plate 39, figs. 6 a, b, c, and d. 
yphonhy lium Caltcola White & Whitfield, 1862, Proc. Bost. Soc. Nat. Hist., vol. viii, 
p. 305. 
Corallum small, subturbinate, more or less curved, moderately but 
irregularly expanding from the base or apex upward, flattened on the 
outer side of the curvature, especially at the lower portion, but else- 
where somewhat regularly rounded; apex small, pointed; exterior sur- 
face rugose from unequal growth; calyx moderately deep; fossett sit- 
uated subcentrally, but extending towards the side of the convex 
curve of the corallum ; principal rays about thirty ; secondary rays about 
equal in number with the principal ones, but they are usually very small 
and inconspicuous. 
Extreme length of an average example, 18 millimeters ; diameter of 
calyx, about 9 millimeters. 
The flattening of the corallum upon the outer surface is more con- 
spicuous upon some examples than upon others, but is always sufficient 
to serve as a ready means of recognizing the species. When the original 
description of this species was written it was referred to Lophophyllum, 
but more careful examination of other and more perfect examples shows 
that it does not possess the characteristics of that genus. 
_ Position and locality.—The original type specimens of this species were 
obtained from the very base of the Burlington limestone division of the 
Subcarboniferous series, where it is associated with the preceding species, 
and where also it is found to range down into the underlying strata of 
the Kinderhook division. Itis also among the collections sent to the 
United States National Museum by Professor Broadhead, who obtained 
it from the top of the Choutean limestone (Kinderhook division of the 
Subcarboniferous) at Sedalia, Mo. (See remarks following description 
of Lithostiotion microstylum, on a subsequent page.) 
Genus HADROPHYLLUM Edwards & Haime. 
HADROPHYLLUM GLANS White. 
Plate 39, figs. 5 a and Db. 
Zaphrentis glans White, 1862, Proc. Bost. Soc. Nat. Hist., vol. ix, p. 32. 
Corallum small, general form depressed- subglobose ; apex small, 
prominent ; calyx. never distinctly concave, but often convex, with a 
receding bat distinet margin, which is short-oval in outline and very ob- 
lique to the axis of the corallum; septal fossett moderately large but 
not deep, ranging with the long diameter of the calyx, its outer end 
reaching nearly to the distal caly cular border; rays well developed, the 
principal ones being from thirty to forty in number, besides humerous 
- rudimentary rays s alternating with the former. 
