282 GEKERAL GEOLOGY. 



durable building stone. Although the fossils are generally in 

 an imperfect and comminuted condition, the following forms 

 have been identified from this horizon: Fusulina cylindrica, 



not uncommon, Cyathaxonia , crinoidal remains, two or 



three forms of Polyzoa, Jlemipronites crassus, (?) Chonetes meso- 

 loba, Productus cequicostatus^ Athyris subtilita, Martinia lineatus, 

 M. planoconvexa, Meekella striatocostata, Syntrielasma hemiplicata, 

 Myalina subquadrata (sp. ?), Aviculopecten occidentalis (? ), Pinna 



, Allorisma lata(?\ Loxonema , Pleurotomaria 



Bellerophon crasms (?). 



No. 41. Yellow and light colored shales; ten to twenty 

 feet. 



No. 42. Lonsdale coal. The thickness of this bed ranges 

 from fifteen to thirty inches ; it is a light, brittle coal, usually 

 quite free from impurities. At Lonsdale's mine, on Deer 

 creek, Guthrie county, this horizon is finely displayed. Also, 

 at Huggin's mine on the west side of the Middle Raccoon, 

 three miles above Redfield, and in the vicinity of Hammonds- 

 burg in Warren county, a coal is found which, in connection 

 with the overlying fossiliferous shales, exhibits an unmis- 

 takable identity with the Lonsdale bed. 



v "" No. 43. Bituminous shales, locally calcareous, indurated ; 

 two to four feet. This is one of the most interesting palseon- 

 tological horizons in the coal-measures, although the number 

 of species is limited, contrasted to the abundance of indi- 

 viduals. From the prevalence of a molluscean fauna for the 

 the most part consisting of diminutive species, or dwarfed 

 individuals of larger forms, it brings strongly to mind 

 certain horizons in the Upper coal-measures of southwestern 

 Iowa. The following is a list of the species identified from 

 this bed : Productus longispinus, P. wquicostatus, Chonetes 

 mesoloba, Hemipronites crassus, (?) Athyris subtilita, Martinia 



planoconvexa, Edmondia , Leda bellastriata, Nucula (?) 



, Gervillia — , Pleurotomaria , P. , 



Macrocheilus , Bellerophon carbonaria, Orthoceras 



Nautilus . 



No. 44. Shales, passing upwards into shaly sandstone, 



