GEOLOGICAL LND GEOGRAPHICAL DISTRIBUTION. 137 



A STRATIGRAPHICAL LIST OF ALL KNOWN BLASTOIDS, 

 ARRANGED GEOGB \ 1MI1CALLY. 



This list does not include some undescribed American species which we have seen, 

 and is not to be regarded as anything more than a table of the results of our own 

 investigations. These are necessarily incomplete in the case of many foreign 

 Blastoids, ns regards both systematic and stratigraphical position. The names of all 

 species with which we are personally acquainted are marked with an asterisk *. 



We have inserted a 1 after a generic name when we are not quite certain as to the 

 systematic position of the species ; but the name employed is the one which seems 

 to us to be the most suitable. 



In those cases where the want of material or of adequate figures has entirely 

 prevented us from determining the generic position of a species, we have put the 

 original generic name within square brackets [ ]. 



UPPER SILURIAN. 



NORTH AMERICA. 



Niagara Group = Wenlock Limestone. 



Troostoblastidoe. 



*Troostocrhms Reinwardti, Troost, sp. 

 [Pentreurites] subcylindricus, Hull is Whitfield. 

 [Codaster] pentalobus, Hull. 



Codasteridse. 



Codaster? pulchellus, Miller fy Dyer. 



DEVONIAN. 



NORTH AMERICA. 

 A. Lower Devonian. 



Upper Helderberg or Comiferous Group. 

 Nucleoblastidae. 



*Ela2acriuus angularis, Lyon, sp. 

 Elaeacrinus Conradi 1 , Hull, sp. 

 *Elseacrinus Verneuili, Troost, sp. 2 

 *Elseacriiras Verneuili, var. pomum, E. \ C, var. 

 1 Possibly only a variety of K. Verneuili. 



- Shumard (Trans. St. Louis Acad. Sri. 1 silo, vol. ii. no. 2, p. 369) includes with this species Pentremites 

 carioides, Owen, a form we are not acquainted with. 



T 



