TRANSACTIONS OF THE SECTIONS. 91 
be taken for a Fenestella, and even approaches certain species of Chetetes (Monticu- 
hora); but its internal structure proves it to be an indubitable Ptilodictya. Loc. 
Cincinnati Group, Cincinnati, Ohio. 4 
6. Fenestella nervata, Nich.—A form somewhat resembling F. tenwiceps, Hall, but 
distinguished by having the frond supported by strong, rounded, slightly diverging 
ribs, like the midribs of a multicostate leaf. Loc. Guelph formation, Cedarville, Ohio. 
7. Ceramopora Ohioensis, Nich.—This very remarkable Polyzoon forms thin 
crusts upon various Brachiopods and Corals, and in its best preserved condition is 
very readily recognized by its diagonally intersecting cells, with thin and arched 
upper walls and oblique semicircular mouths. Joc. Cincinnati Group, Ohio. 
Descriptions of New Species of Cystiphyllum from the Devonian Rocks of 
North America. By H. Atterne Nicnorson, M.D., D.Sc., FBS. 
No less than seven species of Cystiphyllum have already been recorded as oc- 
curring in the Devonian rocks of North America, viz. C. vesieulosum, Goldfuss, 
C. Senecaense, Billings, C. grande, Billings, C. suleatum, Billings, C. Americanum, 
Edw. & H., C. aggregatum, Billings, and C. mundulum, Hall. To these the author 
now added the following three species, all of which were obtained by him from the 
Corniferous Limestone of Canada and the State of Ohio. 
1. Cystiphyllum Ohioense, Nich.—This is a very minute species, averaging not 
more than six lines in length, with a remarkably deep, pointed, and not oblique 
calice. It possesses very distinct septal striz, but is not furnished with any radici- 
form prolongations of the epitheca. It is most nearly allied to C. mundulwm, Hall, 
from the Devonian of Rockford, Iowa, but is distinguished by its smaller size, the 
smaller number of its septa, and its much deeper and more pointed calice. 
Loc. Common in the Corniterous Limestone of Columbus, Ohio. 
2. Cystiphyllum squamosum, Nich.—This species is readily distinguished by its 
extraordinarily flattened and scale-like form, due to the extreme obliquity and 
shallowness of the calice, the flattening of the dorsal surface, and the total disap- 
pearance of the lateral surfaces. No other species of the genus even approaches C. 
sguamosum in these characters, and these are therefore of themselves sufficient to 
characterize the species. Loc. Corniferous Limestone, Columbus, Ohio. 
38. Cystiphyllum fruticosum, Nich.—This species is remarkable for being compound, 
and for forming large colonies composed of numerous cylindrical, straight or slightly 
flexuous corallites, which are about three lines in diameter, and are placed about two 
lines apart. The internal structure is that of Cystiphyllum. Its composite character 
sufficiently distinguishes C. fruticoswm from all previously recorded species of the 
enus except C. aggregatum, Billings, and from this it is separated by its totally 
Gifferent form and mode of growth. Joc. Corniferous Limestone, Wainfleet and 
Walpole, Ontario. 
On the Columnar Form of Basalt. By W. Cuanpier Roxerts, F.C.S. 
The author briefly stated what were the views hitherto held by geologists as to 
the method by which the jointed prismatic structure had been produced. He spe- 
cially alluded to the experiments made in 1804 by Mr. Gregory Watt, who showed 
that when basalt was melted and slowly cooled, globular structures appeared in the 
solidifying mass, a fact which led Mr. Watt to believe that the mutual compression 
of such spheres resulted in the formation of hexagonal prisms. The author pointed 
out the objections to this theory, and described the results of experiments he had 
made on the effect of heat on certain brick-like masses of fire-clay and sand. When 
these masses are heated to redness (a point far below that at which they would fuse), 
they contract from 3 to 4 per cent., and the unequal strain which attends the con- 
traction produces a columnar structure closely resembling that of certain beds of 
basalt which occur in the valley of the Ardéche. 
This structure can be produced at will, but it is necessary that the fire-clay should 
not be uniformly heated. 
He concluded by comparing the columnar form of starch, which had assumed its 
