C. D. Walcott — Position of the Olenellus Fauna. 31 



I. New York and Vermont. — The Olenellus fauna appears 

 to have a great vertical range in New York, as shown by the 

 Cambrian strata of Washington and Rensselaer counties. I 

 have called it 14,000 feet,* but this may be modified by a more 

 detailed study of the sections. About 2,000 feet from the 

 summit of the strata assigned to the Cambrian, the fauna con- 

 tains Olenellus asaphoides but with it occurs the species Lin- 

 gulella Granvillensis, Linnarssonia sagittalis var. Taconica, 

 Agnostus desiderata, Agnostus of the type of A. pisiformis, 

 Microdiscus connexus and Zacanthoides Katoni, all of which 

 are representative species of the Paradoxides fauna. Professor 

 W. B. Dwight has recently permitted me to examine the type 

 specimens of Olenoides Stissingensis Dwight, Leperditia 

 ebinina Dwight, and Kutorgina Stissingensis Dwight, from the 

 Middle Cambrian strata of Dutchess County, New York. 

 None of these species occur in the Olenellus fauna, and the 

 Olenoides belongs to the type of the genus occurring in the 

 Middle Cambrian rocks of Utah. Kutorgina Stissingensis is 

 the representative of Kutorgina Labrador ica of the Lower 

 Cambrian, and Leperditia ebinina belongs to a division of the 



fenus that includes a similar type, from a bed referred to the 

 [idclle Cambrian, in the Grand Canon section in Arizona. 

 These species indicate that the Middle Cambrian fauna of 

 eastern New York has the general facies of that of the Southern 

 Appalachian and Rocky Mountain provinces. 



In the Georgia section of Northern Vermont the Olenellus 

 zone has a thickness of about 500 feet.f "With the possible 

 exception of Ptychoparia Adamsi none of the species are 

 known to range upward in the section. 



Rooky Mountain Area. — In the Rocky Mountain area the 

 Eureka District and Highland Range sections show the rela- 

 tions of the Lower, Middle and Upper Cambrian faunas.;}: In 

 each section the Olenellus fauna is confined to a comparatively 

 narrow zone, just above the non-fossiliferous quartzite. 



In the Eureka District the fauna consists of but six species : 

 Kutorgina Prospectensis, Scenella conula, Olenoides quadri- 

 ceps, Olenellus Gilberti, O. Iddingsi and Anomocare parvum. 

 Of these, two species, Olenoides quadriceps and Scenella 

 conula, are found 500 feet higher in the section.§ 



The Olenellus fauna, in the Highland Range section, in- 

 cludes only Olenellus Gilberti and O. Lddingsi.\ One hun- 

 dred feet higher in the section Hyolithes Billing si is found, 

 just as in the Eureka section, Stenotheca elongata occurs 2,000 



*This Journal, III, vol. xxxv, 1888, p. 242. 



•I- Bull. U. S. Geol. Survey, No. 30, 1886, pp. 15-20. 



X Bull. U. S. Geol. Survey, No. 30, 1886, Introduction. 



§ Op. cit., p. 32. || Op. cit., pp. 33, 34. 



