Prosser — Hamilton and Chkmuxo Series. 



171 



1. Spirifer mucronatus (Con.). Bill., var. posterus, H. and C. (r) 



2. Liorliynchus mesacostalis, Hall (?). (it) 



3. Modiomorpha cf. subalata (Con.), Hall. (it) 



No umbonal ridge is shown and so it departs from the form of 

 this species. The nrabonal slope being rounded, the specimen may 

 belong to the genus MT/ymella. 



On the hillside, eighty feet above the road, are thin, apparently unfos- 

 siliferous sandstones (A 6 ). These two exposures are in the Ithaca formation. 



XX A*. One hundred feet lower than A 5 , thin, micaceous sandstones 

 alternating with shales, are well exposed along West brook. The surface of the 

 thin sandstones is usually shiny, but some specimens have a glazed, blackish 

 surface in which specimens of Fucoides grapliica, Van., occur. These rocks 

 are in the Sherburne formation, the top of which is probably not much above 

 this outcrop. This ledge is 390 feet above the railroad station in New Berlin, 

 or approximately 1,478 feet A. T. The thickness of the rocks from this out- 

 crop down to the top of the Hamilton formation, as exposed on the banks of 

 West brook in the edge of New Berlin village, is 255 feet, which is approxi- 

 mately the thickness that we have assigned to the Sherburne formation of 

 Chenango county. Farther down the brook and some seventy feet lower is a 

 rocky glen which gives an excellent idea of the Sherburne shales. The rocks 

 are mostly bluish or blackish shales, forming steep banks on each side of the 

 brook, with only sufficient space between them for the stream and highway. 

 This formation continues down the brook into the edge of New Berlin village. 



XX A 3 . The base of the Sherburne formation occurs in West brook at 

 the beginning of the former mill race and upper dam, just above the old 

 brewery. This locality is now on the farm of Thomas Lowe, at which place 

 the thin, bluish-grey, smooth sandstones and shale of the Sherburne formation 

 are clearly shown resting directly on the bluish-black, coarser arenaceous 

 shales of the Hamilton. There is apparently no representation of charac- 

 teristic Tully limestone and Genesee slate. Fossils appear in the Hamilton 

 shales just below the dam and, a little lower, the creek has cut a narrow 

 gorge through these rocks with walls from twenty to twenty-five feet high. 

 The top of the Hamilton is about 135 feet above the railroad level at New 

 Berlin station, or approximately 1,223 feet A. T. These upper shales of the 

 Hamilton are quite fossiliferous, but the number of species is small. The 

 following were found in the shales just below the dam and above the gorge: 



1. Spirifer mucronatus, (Con.), Bill. (c) 



2. Spirifer Tullius, Hall. (c) 



