14 LOWER PENINSULA. 



losed with the spinulose projections. Coenenchym composed of 

 very stout vertical lamels, with delicate transverse leaflets intersect- 

 ing them. Intervals between the tubes about as large or larger 

 than a tube diameter. Growth pyriform or globular. Found in 

 the drift deposits of Michigan. Common in the Niagara group of 

 New York, Indiana, and Kentucky. 



Plate III., Fig. 2. — The two lower specimens, both silicified, are 

 from Paul's Station, Indiana. 



LYELLIA. 



Milne Edwards. 



Visceral tubes circular, with orifices projecting above the general 

 surface, radiated by twelve conspicuous vertical rows of spinules, 

 and transversely septate by subplane diaphragms. 



Coenenchym abundant, formed of convex, vesiculous, horizontal 

 plates of unequal size, extending in interlacing layers across the 

 intertubular interstices, and inclosing blister-like cavities much 

 resembling the vesiculous tissue of a Cystiphyllum. 



LYELLIA AMERICANA, Milne-Edwards. 



Synon., Heliolites macrostylus, Hall. 



Tubes 1 1 to 2 millimeters wide, radial crests almost extending 

 to the centre, and decurrent on the outer projecting part of the 

 orifices, but not prolongated across the interstices, which are 

 divided into a network of irregular angular cell spaces, or are, in 

 weathered specimens, of blistered aspect. Transverse diaphragms 

 subplane, often warped, closely set. Interstices between the tubes 

 larger than one tube diameter. Vesiculous plates of coenenchym of 

 irregular, coarser, or smaller size, frequently found partially de- 

 stroyed by decay, in which cases the tubes present themselves as 

 free, longitudinally carinated columns, held together by such of the 

 coenenchym as escaped destruction. Some of the specimens of 

 Sarcinula represented by Goldfuss are doubtless weathered speci- 

 mens of Lyellia. {Vide Sarcinula costata, Goldf. Tb. 24 f. 11.) 



