Maryland Geological Survf.y 2Gr 



mm. Zooecia rounclccl, 5 to 6 in 2 mm., witli a small distinct lunarium 

 overarching the cavit3\ Interzocecial space tlat and granulose in some 

 portions of a specimen, but in others, probably more mature areas of the 

 same zoarium, occupied by a ridge-like wall bearing the small overarching 

 lunarium and causing the aperture to be enclosed in a polygonal area. 



Internally this species is very similar to associated species of the genus 

 as indicated on pi. xlvi, although a marked difference is noted when the 

 thin section passes through the outer ridge-like wall. This latter character 

 in connection with the growth habit and dimensions of the zooecia is suffi- 

 cient for its ready recognition. 



Occurrence. — Helderberg Formation, Keyser Member. Cash 

 Valley. 



Collections. — Maryland Geological Survey, U. S. National Museum. 



Genus CHILOTRYPA Uliich 



Zoarium small, ramose; branches hollow, lined internally with an 

 epitheca, the central tube being narrow and equal in diameter throughout, 

 or rather large, with irregular contractions and expansions. Zoa^cial 

 apertures elliptical, oblique, the lower margin thickened and elevated ; 

 diaphragms few or absent: interstitial vesicles commonly occupied by a 

 dense calcareous deposit near the surface. 



Type: CMlotrypa Mspida Ulrich, of the Chester. 



The species described below^, together with others discovered in the past 

 ten years, necessitates a slight change in the original diagnosis of the 

 genus. The description and original figures of Callopora venusta Hall, 

 the type of OcBlocaulis Hall and Simpson, indicate that Ccelocaulis is 

 a synonym for Chilotrypa. However, in Natui'al History of New York, 

 Palaeontology, Vol. VI, pi. 23a, additional figures are given and these 

 indicate other relationships for Coelocaulis, figs. 1 and 2 showing alliance 

 with Diamesopora, while figs. 3 to 5 indicate relationship with Lioclema 

 or possibly Nicholsonella. It is impossible that these various figures could 

 have been made from specimens belonging to the same species or even 

 genus, and until the original specimens are reexamined and their char- 

 acters verified, the validity of Coelocaulis as a genus must remain doubtful. 



