352 G. H. CHADWICK STEATIGRAPHY OF XEW YORK CLINTON 



* 

 IRONDE QUOIT LIMESTONE 



Hartnagel, 1907 (8: 16-17). In its lower shaly half at Kochester the 

 Irondeqiioit limestone appears to comprehend western phases of the 

 PhoeniXj or perhaps Brewerton (text-figure 3 illustrates the causes of 

 uncertainty), and it is even possible that it embraces an important hiatus, 

 in which case the name might be restricted to the upper crystalline part 

 with its curious ^'reefs"^ ^^ and Eochester faima. Preferably it could be 

 retained in its original scope for the western sections not susceptible of 

 easy subdivision. It is interesting to note that Hall hesitated whether or 

 not to include the Irondequoit limestone in the Eochester (Xiagara) 

 shale, and felt obliged (2 : 82) to present his reasons for adding it to the 

 Clinton. These reasons still apply to its lower and major portion. The 

 fossils listed are derived mostly from the upper half : 



Buthotrephis gracilis crassa 

 Receptaculites tessellatKS 

 Favosites niagarensisf 

 Glhilotrypa ostiolata 

 Hallopora elegant ul a 

 Orthis ftahclUtes 

 Bilodites WoM 

 RhipidomeUa hydrida 

 Brachy prion prof nudum 

 Leptcena rJioinJjoidah's 

 Spirifer radiotus 

 Spirifer crispus (8 :1T) 

 Cyrtia meta 



Rhyncliotreta amcricana (12 :310) 

 Rhyncliotreta rol)u.sta (10:7) 

 Camarotcechia acinus (5 :193-194) 

 CamarotcecMa neglect a (8 :17) 

 Atrypa reticularis affinis 

 Atrypa nodostriata 

 Whitfieldella nitida 

 Whitfleldclla cylindrica 



Whitfieldella intermed ia 

 Whitfieldellanaviformis 

 Anastropliia interplicata 

 Clorinda fornicata 

 Pisocrimis glohosus 

 Pisocrinus pyrifoniiis 

 Stephanocrinus gemm iformis 

 Closterocrinus elongatus 

 Caryocrinites ornatus 

 StropJiostylus cancellatus? (3 :91) 

 ".^" CycJostomiceras? a'brnptum 

 Protol^ionoceras crehescens (?) 

 Da wsonoceras americanum 

 Cycloceras "i^nhricatum" 

 Cornulites cUntoni 

 Calymene niagarensis 

 Trirtierus delpliinocephalus 

 Bumastus ioxus 

 Perhaps also : 

 ? Goldius niagarensis (13:559, 1488) 



Except for the forms that are unique, this list is overwhelmingly of Eoch- 

 ester species, though it still lacks over one hundred of the indicial species 

 of the Eochester shale. ^^ It is hard to see on what grounds it should be 

 subordinated to the Clinton group. AYe have in the uppermost beds 

 usually assigned to the Irondequoit limestone a great inrush of the Eoch- 

 ester-Waldron fauna. These beds have more than twice as many species 



15 Sarle (Am. Geol., vol. 28, p. 284) reports 99 species as found in the "reefs," but his 

 lists of species are not publislied. See also Am. Nat., vol. 16, p. 711 ; Am. Geol., vol. 1, 

 p. 264 ; Kept. N. Y. Pal. for 1899, p. 672, and for 1901, p. 428. 



