On CalamoporcB in gravel deposits near Ann Arbo?-, Mich. 397 



meters, in the same specimen. Twelve longitudinal linear sulci 

 are well marked. 



The pores are moderate in size and in number, surrounded bj 

 a prominent rim and forming one or two irregular rows on 

 each side, 



Calamopora WinckeUi, n. s. 



Tubes rounded, or obtusely polygonal, from three to four mil- 

 limeters wide, interspersed with many smaller ones. Walls 

 marked with 12 longitudinal sulci but otherwise smooth. Dia- 

 phragms distant, simple, flat, promiscuously horizontal, or in all 

 degrees of obliquity ; frequently they become flexuous, by lateral 

 depressions, or one of these depressions is so strongly developed 

 as to occupy the whole diaphragm, and to transform it into a 

 fonnel. 



Pores are large, surrounded by a rim, moderately numerous, 

 forming from 8 to 12 rows on the circumference of a tube. 



The corallum occurs in irregular subglobose masses. A piece 

 of epithecal crust preserved in a specimen has, besides the con- 

 centric lines of growth, also fine longitudinal striae. It is found 

 enclosed in the same rocks with the formerly described species ; 

 one specimen I took from a sandstone boulder, containing a 

 number of fossils characteristic of the Oriskany sandstone. 



It grows in large undulated expansions, of a thickness variable 

 from a few lines to more than an inch. From the surface of 

 these similar expansions sprout up, forming gradually a cavern- 

 ous superstructure, the floors of which, on the under side, are all 

 covered with an epitheca, so thin that the outlines of the tubes 

 show through it. Its tubes are of two sizes, and so disposed as 

 to give to the surface the appearance of a Heliolites. The larger 

 ones are perfectly round, and measure about one milhmeter, the 

 smaller ones are ant^ular, and are only half a millimeter wide. 



Twelve distinct longitudinal ridges can be observed on the 

 casts of the larger tubes, and also on the smaller tubes longi- 

 tudinal striae can be noticed, n T -L 



Both kinds of tubes are divided by regular perfect diaphragms. 

 In the larger tubes, the intervals between the diaphragms ex- 

 liibit a small number of linguiform lamelte, similar to those of 

 Calamopora hemispherica, or C. epidermata. 



Pores surrounded by an elevated border, quite numerous on 

 the larger tube as well as on the smaller ones. 

 Calamopora heliolitiformis, n. s. 



Differs from the former species by having larger tubes, and by 

 its growth in subglobose masses and not in flat expansions. 



