102 



EOCENE AND LOWER OLIGOCENE CORAL FAUNAS. 



rather reaular crowns. It can scarcely be doubted that the species is a 

 genuine Trochocyathus. 



The size and relations of the dimensions of different specimens are so 

 variable that we give no measurements; the figures give the same data in 

 more comprehensive form. 



Locality. — Ncar Clayton, Contra Costa County, California. (Stanton.) 



Horizon. — Tejou bcds (upper part). 



Trochocyathus zitteli Merriam. 

 PL VIII, figs. 4 to 7. 

 1897. ri(tc(>.imili(( 11. sp. Merriam. Journ. Geo!., VoL V, p. 770. 



Doctor Merriam very kindly sent me six specimens of this species, and 

 on that material the following description is based. 



The form of the corallum is short cornute, curved in the plane of the 

 shorter transverse axis of the calice. 



The following are measurements of five specimens: 



Greater dianieter of calice 



Lesser <liaineter of calice 



Height of corallum I 12 



The best preserved of the five specimens showed at the base a small 

 nipple-like pedicel, with a minute scar of attachment. Another speci- 

 men showed some slight sinuosity of the wall parallel to tlie vertical axis 

 of the corallum near the calicular margin. Costse correspond to all septa; 

 thev are distinct but not very prominent, have rather broad bases, with 

 somewhat acute edges. They are quite regularly alternately larger and 

 smaller in size; are granulate, the granulations rather large, often a distinct 

 row along the summit of a costa. Septa numerous; 72 were i-ounted in the 

 cross section of a specimen whose greater diameter is lo.S mm. and lesser 

 diameter IS.f) mm. Considering six as the number of the primary cycle, 

 there would be four complete cycles and half the members of the fifth, 

 but the various cycles are not distinctly indicated. The septa are not very 

 long, somewhat or decidedly thicker at the wall, inner portion thin, and 

 are usualh- verA' flexuous. A few granulations on the septal faces. There 



