164 W. I. Robinson, 



late calcareous tissue. Septa represented by striae only. Walls 

 thick, traversed by minute irregular canals or pores." 



By comparing the above original descriptions it may be seen 

 that there is no essential character to distinguish between them. 

 A comparison of the original figures of Michelinia? geoniefrica 

 Edwards and Haime, which is the genotype of Cleistopora, with 

 the type specimen of Leptopora leaves no doubt that the genera 

 are identical. 



List of Species. 



Leptopora typa Winchell. Genotype. 



Proc. Acad. Nat. Sci. Phila., Vol. XV, 1863, 1864: 3. 



Locality and horizon: Burlington, Iowa. Mississippian (Kin- 

 derhook). 

 Leptopora winchelli White. 



Bull. U. S. Geol. Geog. Surv. Terr., Vol. V, No. 2, 1879: 211. 



Locality and horizon: Near forks of Logan River, Bear River 

 Range, North Utah. Mississippian. 

 Leptopora placenta (White). 



Michelinia? placenta White. Cont. Ind. Pal., No. 8, 1880: 157, 



PI. 39. 



Locality and horizon: Sedalia, Missouri. Mississippian 

 (Chouteau). 

 Leptopora expansa (White). 



Michelinia expansa White. Cont. Ind. Pal., No. 8, 1880: 158, 



PI. 39- 

 Locality and horizon: Sedalia, Missouri. Mississippian 



(Chouteau). 

 Leptopora gorhyi Miller. 



17th Ann. Rep. Geol. Surv. Ind., 1891, 1892:616; adv. sheets, 



1891 : 6. 

 Locality and horizon: Near Sedalia, Missouri. Mississippian 

 (Chouteau). 

 Leptopora procera Rowley. 



Am. Geol., Vol. XXVII, 1901 : 349- 



Locality and horizon: Annada, Missouri. Mississippian 

 (Chouteau). 

 Leptopora ramosa Rowley. 



Am. Geol., Vol. XXVII, 1901 : 349. 



Locality and horizon: East of Curry ville, Missouri, associated 

 with L. placenta. Mississippian (Chouteau). 



