40 



Kepokt of the State Geologist. 



not always continuous and not impregnated with StyUolina, but containing 

 representatives of the Intumescens-fauna, some of which have been elsewhere 

 observed only in the Naples beds above. It is an early appearance of these 

 species not recorded in the more western sections.* 



The interbedded soft shales of the lower part of the Naples beds bear 

 most abundantly the characteristic fossils of the fauna. As the sandstones 

 increase upward at the expense of the argillaceous sediments the fossils become 

 less profuse. In the carefully studied Naples section, the continuation of this 

 fauna is through a series of deposits measuring 599 feet,f that is to say, from 

 the first appearance of greenish sandy sediments with representatives of thk 

 fauna to the first incursion of a distinct brachiopod fauna. This latter, foreign 

 in its composition to that characterizing the Naples beds, occurs just below 

 the heavy sandstones of the Naples section, which have been regarded % as 

 continuous with the original "Portage sandstones" of Professor Hall. This 

 faunule embraces the following species : 



LiorhyTichuSf a large shell at maturity, having the aspect of L. quadricos- 

 tatus, but with well developed lateral plications ; 



Produotella speciosa ; 



Airypa reticularis ; 



Leptostrqphia macro nata 



Ordiculoidea, sp. 



This is not an association indicating any definite relationship to the true 

 Chemung fauna, and may properly be looked upon as one of the already men- 

 tioned incursions into this region of species of the eastern fauna. 



Less than one hundred feet above this horizon and at different intervals 

 in the next five hundred feet, occurs a typical Chemung fauna with Orthis 

 Tioga and Dictyosponges ; and these beds are followed directly by the High 

 Point strata carrying Spirifer disjunctu.s, MhyrvcTumeUa pugnus, etc.§ 



*An enumeration of the species of this faunule was given by the writer in Dr. Lincoln's Report on the Geology of 

 Seneca county (Fourteenth Ann. Rept. N. Y. State Geol., foot note to pp. 100-101, 1S95.) 

 t Luther, in Thirteenth Ann. Rept, N Y. State Geol., p. 119, 1894. 



X In all previous papers bearing upon the thickness of the Portage formation in the Naples section the apparent extinc- 

 tion of the Naples fauna at the elevation above stated has been regarded as evidence that the heavy-bedded sandstones 

 directly overlying that horizon were to be interpreted as equivalent to, and continuous with the original " Portage sand, 

 stones " of the Genesee section. The discrepancy in the thickness to be assigned to the formation in these two sections has 

 also been frequently referred to; in the Naples section it is about 600 feet, while in the Genesee section, with the addition of 

 l he Wiscoy beds above the Portage sandstones, the thickness is fully twice that. With our present knowledge this is still a 

 proper statement of the unequal vertical range of the Naples fauna in adjoining regions. Latest investigations now Indicate 

 that the true horizon of the "Portage sandstones" in tne Naples section is not less than 400 feet above the last appearance of the 

 Naples fauna. These beds have been traced eastward from the upper Portage fall with much care by Mr. D. D. Lutheh and his 

 observations suggest that there may be no such discrepancy in sedimentation in these two sections as nas been before 

 believed But these additional 400 feet of strata are permeated with Chemung fossils and, if they actually lie below the 

 horizon of the ' Portage sandstones" we are presented with a condition which not alone renders the employment of the 

 term Portage difficult in any case but also emphasizes the early statement of Professor Hall (Geology of the Fourth District 

 p. 249) : " It may thus happen that the fossils so typical of the Chemung group commenced their existence in the eastern 

 part of New York much earlier than in the western part ; and, therefore, the strata equivalent in age to the Portage group 

 may there contain fossils which at the west appear only at a later period." 



{ A full list of the species of the High Point fauna i« given in Bull. 16, U. S. Gaol. Surv. ; The Higher Devonian Faunas of 

 Ontario connty p. 78. 



