CORRELATIONS EASTWARD 335 



aboiits. Tlie vertical allocation of this partial section on the chart has 

 been guided by these two criteria quite as much as by the evident link 

 that it furnishes between the lower portions of the South Granby and 

 Lakeport columns. The fossiliferous olive shales at Brewerton, although 

 their few fossils are largely Eochestcr shale species (11:58), are thus 

 found to be far doAvn in the Clinton, below the base of the true Rochester 

 shale. The latter, however, is exposed (judging by character, fossils, and 

 contiguity to Lockport outcrops) a couple of miles northeast of Three 

 River Point (11 : 58), while the olive shale at Phoenix (loc. cit.), near by, 

 can be but a little lower in the sequence, though characteristically Clinton. 

 Most important of all the drillings is that at Lakeport, which com- 

 mences in the Lockport and terminates in apparently the Oneida, though 

 jjossibly a bit higher. Besides giving a maximum measure* of the New 

 York Clinton, and seeming to confirm the position of the shales at Brew- 

 erton in the highly fossiliferous zones penetrated about midway of the 

 well (135 to 171 feet depth), this bore hole adds two new ore horizons 

 and completes the list of known subdivisions in the Clinton group of New 

 York State. Before continuing eastward (it is but 25 miles to Clinton) 

 it will be well to summarize these subdivisions with their thicknesses at 

 Lakeport and the names presently to be formally proposed for them. 

 From the top doT^aiward they are : 



Thickness in 

 Name used in this paper. Lakeport well. Comments. 



Lockport dolomite (undivided) . . 14 feet sliowii Probably at least 100'. 



Gates limestone Absent (hiatus) . . . 20 feet at Rochester. 



Rochester shale 29 feet Upper half missing ( ?). 



Lakeport limestone 16 feet Considerable shale. 



Donnelly iron ore 1 foot In limestone. 



Phoenix (Schroeppel) shale 62 feet With calc. sandstone. 



Kirkland limestone and ore 6 feet Highly crinoidal. 



Brewerton shale ! . 36 feet With many fossils. 



Williamson shale 105 feet Dark shale in part. 



Woleott Furnace iron ore. ..... . Absent (hiatus?).. See Wolcott section. 



Woleott limestone 18 feet. Here mostly shale. 



Verona iron ore 3 feet Important to east. 



Sodus shale with lime lentils. . . , 31 feet Purplish to west. 



Sterling Station iron ore Trace only See note below. 



Reynalcs limestone 7 feet Here mostly shale. 



Unnamed dark shale 7 feet Part of Reynales? 



Furnace ville iron ore° 1 foot Sec note below. 



^ Somewliat exceeded in the Cliittenango well a few miles south. 



^ The identification of the basal ore bed hero and at Brewerton as a reappearance of 

 the Furnacevillc instead of an extension of the Sterling Station ore may he erroneous, 

 bi^t it involves us in fewer diflaculties to find the latter in the "trace of ore" occurring 

 at the proper interval above this one. Text-Iigure 4 shows how easy a different correla- 

 tion would be, though the black pebble zone supports that here made. 



