PALEONTOLOGlC CLASSIFICATION 



19S 



Notwithstanding the tendency or policy of establishing formational 

 units on lithologic grounds, I wish to renew the suggestion that the 

 Galena series, and the Maquoketa series as well, be divided into forma- 

 tions with stratigraphic and faunal definition. The term Beloit forma- 

 tion should extend as before described, including all the range of Orthis 

 subcequata, Con. The top of this formation comprises the Fucoid bed, in 

 which Orthis lynx, Eichw., and Orthis pectinella, Emmons, occur, the for- 

 mer ranging upward, the latter being limited to that zone. The top of 

 this formation can be located by these easily found and recognized species. 

 The Galena formation shoxild include the Orthisina zone, in which are 

 the first Eeceptaculites-bearing strata, and extend upward preferably to 

 the top of the zone of Madurea cuneata, Whitf . — that is, to the top of the 

 "cap rock" at Dubuque, Iowa. The strata of irregular limestone and 

 interlaminated carbonaceous shales, which extend at Dubuque, Iowa, 

 from the "cap rock" to the blue shales of the Maquoketa proper, I should 

 include in the Maquoketa series and should give to them the new name of 

 Dubuque formation. This formation coincides with the Triplicia bed or 

 zone as previously defined.* In like manner I should distinguish the 

 Maquoketa formation proper from the upper beds, or Wykoff formation. 



Since the preceding paragraphs were written and read before the 

 Society, another Annual Eeport of the Iowa Geological Survey has ap- 

 peared in print, f It includes the report on the Geology of Winneshiek 

 county by Professor S. Calvin. In this report, the part of a synoptical 

 tablej presents the following classification: 



Series 



Stage 



Formation 



Trenton 



Maquoketa 



Brainard shale 



Fort Atkinson limestone 



Clermont shale 



Elgin shaly limestone 



Galena 



Galena limestone 



Decorah (Green) shale 



Platteville limestone 





Saint Peter 



Glenwood shale 



Saint Peter sandstone 



* Loc. cit, vol. 19, pp. 21 to 24. 

 tlowa Geological Survey, Annual Report, vol. 16. 

 tLoc. cit., p. 60. 



