FOSSIL FAUNAS OF THE OLEAN QUADRANGLE 



BY CHARLES BUTTS 



In pursuance of instructions received from the state paleon- 

 tologist, the fullest possible collections of fossils were made 

 from nearly every fossil-bearing outcrop on the quadrangle, 

 including 259 stations. The analysis of the fossil faunas thus 

 collected reveals their distribution according to the accompany- 

 ing lists and seems to warrant the division of the strata into 

 several zones, whose positions in the general stratigraphic 

 succession are exhibited in the following columnar section. A 

 few feet of shale exposed in the deeper valleys near the north- 

 ern margin of the quadrangle are not shown in the section, as 

 no collections were made from it. 



These zones correspond with Mr Glenn's divisions as follows: 

 Zone 2 is the Olean conglomerate, zone 3 is the, Oswayo shales 

 and Knapp beds, zone 4 is the limestone layer, zone 5 is the 

 interval between the limestone layer and the top of the Sala- 

 manca conglomerate, zone 6 is the Salamanca conglomerate, zone 

 7 is the interval between the Salamanca and Wolf creek con- 

 glomerates, zone 8 is the Wolf creek conglomerate, zone 9 is the 

 interval between the Wolf creek conglomerate and the top of 

 the chocolate shales, zone 10 is the chocolate shales and the 

 quarry sandstones, zone 11 is the interval between the quarry 

 layer and the Cuba sandstone, and zone 12 is the latter bed. 



On comparison of the zonal lists, it appears that there is a 

 gradual disappearance of species on passing upward through 

 the strata without the appearance of any new elements till the 

 horizon of the Wolf creek conglomerate is reached. The zones 

 below this horizon are therefore based on this disappearance 

 of species at certain horizons, which gives rise to a slightly 

 different facies to the overlying fauna. The zones do not coin- 

 cide with the vertical range of some one or more characteristic 

 species having definite upper and lower limits. Thus, so far 

 as my collections show, Orthothetes chemungensis 

 does not pass above the top of no. 11, Athyris angelica 

 disappears at the top of no. 10, while at the top of no. 9 all but 

 nine species disappear, and their places are taken in the next 

 zone, the Wolf creek conglomerate, by new genera and species. 



