288 



Report of the State Geologist 



it is extremely abundant, especially in the middle one. The specimens are of 

 fair size, and usually well developed. Occasionally one is found upside down 

 in the rock. 



Genus Streptelasma, Hall. 



152. Streptelasma rectum, Hall. 



1876, Hall, Pal. N. Y. Ills. Dev. Foss., pi. 19. 



This is the most common coral at Eighteen-mile creek. It is abundant in 

 the shale below and between the Trilobite beds, and occasionally occurs in the 

 Nautilus bed. It is common in the S. demissa bed, and extremely so in the 

 lower Moscow shales. 



153. Streptelasma ungula, Hall. 



1876, Hall, Pal. N. Y., Ill, Dev. Foss., pi. 19. 



This species is not very common. It occurs in the lower Moscow shale 

 with the preceding, between three and five feet above the Eucrinai limestone. 



Genus Zaphrentis, Hannesque. 



154. Zaphrentis simplex, Hall. 



1876, Hall, Pal. N. Y., Ills. Dev. Foss., pi. 21. 



This species is comparatively rare. A few individuals were found in the 

 " coral layer " of the Moscow shales twenty inches above the Encrinal lime 

 stone. It is rare in the Encrinal limestone. 



Genus Heliophyllum, Hall. 



1876, Hall, Pal. N. Y., Ills. Dev. Foss., pi. 23. 



155. Heliophyllum IIalli, Edwards and Haime. 



This coral has a very restricted vertical distribution at Eighteen-mile 

 creek, being practically confined to the coral layer of the lower Moscow shales, 

 where it is common. A single specimen was obtained from the S. demissa bed. 

 At Morse creek it occurs in the Encrinal limestone. 



156. Heliophyllum coxfluens, Hall. 



1876, Hall, Pal. N. Y., Ills. Dev. Foss., pi. 26. 



This coral occurs only in the Encrinal limestone. Several specimens 

 were noted in blocks of this rock on the lake shore. On Morse creek it is not 

 uncommon in the lower Encrinal, associated w ith the preceding. 



