328 Report of the State Geologist. 



Chonetes scitula. 



Stropheodonta nacrea. 



Callopora (=Fistulopora) incrassata. 



All of these except the last two species, occur in the typical Spirifer 

 c&nsobrinus fauna of the Eighteen-mile creek region, and S, nacrea occurs in 

 the limestone immediately below. Fistidipora incrassata, has not been noticed. 



The S. consobrinus fauna of the Eighteen-mile creek region then corresponds 

 in a general way to the upper (Widder) division of the Ontario Hamilton. 



The " middle division " of Professor Calvin is characterized by the great 

 development of corals, of which Heliophyllum Ilalli is the abundant and 

 characteristic form. With it occur the following : 

 Cystiphyllum Americanum 

 Heliophyllum juvene. 



Diphyphyllum (= Craspedophyllum) Archiaci. 

 Several species of Favosites. 



Several species of Alveolites, and a number of others. 



Spirifer fimbriatus and Atnjpa reticularis also occur. This fauna ceases 

 abruptly and the upper fauna appears as abruptly. 



That this " middle fauna " bears some relation to the Encrinal limestone 

 fauna of the Eighteen-mile creek region, seems evident. At Morse creek, the 

 lower Encrinal contains many corals, and at Eighteen-mile creek these and 

 especially Favosites, form a characteristic constituent of the fauna. The 

 corals do not disappear as abruptly as they do in Canada, but recur in the 

 lower part of the S. consobrinus fauna. There is thus indicated a uniformity 

 of conditions and similarity of changes over an extensive area. 



At Livonia, N. Y., in the Genesee valley, the Hamilton has a total thick- 

 ness of 517 feet*; 280 feet of this represents the Upper shale, two feet the 

 Encrinal limestone, and 235 feet the Lower shale. The four feet of sandy 

 shale and calcareous layer immediately below the limestone are united with 

 it into the " Encrinal band." 



In order that a comparison between the Livonia section and the Eighteen- 

 mile creek section can be made, it is important that the reference plane here 

 chosen, i. e. the Encrinal limestone or band, is equivalent in the two places. 

 Such equivalency can of course only be determined by their fossils, the mere 

 occurrence of a two-foot stratum of limestone in both localities being of little 

 significance for purposes of correlation. Comparing the fossils of the two 

 limestone beds, we find only one of the species given in the Livonia list 



* D. D. Luther, Report. N. Y. State Qeol. 1893. 



