10 



a. Seven feet of grayish and purplish shales with bands of 

 bituminous shales. Towards the to]) these shales weather 

 considerably, but farther down they are more resistant, and 

 large thin slabs may be obtained. 



h. Eighteen inehes of bituminous black shales, with two 

 bands of limestone, eaeh an inch in thiekness, and made up 

 of the exuviae of the minute pteropod Stvliolina fissurclla 

 (Hall). 



This latter mass contains an interesting association oi 

 fossils, representing a commingling of Hamilton and Genesee 

 species, but with a preponderance of the latter. Lunulicar- 

 dium fragile (Hall) is the most abundant fossil in the black 

 shale, and with it occurs Stvliolina Bssurella (Hall), though 

 not very commonly, except in certain places. Lingula 

 spatula ta ( Vanuxem ) is a fairly common and well preserved 

 shell, passing through several variations. Orthoceras and 

 Bactrites are represented by small species, and these with 

 Coleolus aciculum ( Hall ) are frequently replaced by iron 

 pyrites. Goniatites are rare, a few small specimens having 

 been found, including G. lutheri (Clarke). Spirifer tullius 

 (Hall) is fairly w T ell represented for a normal Hamilton 

 species. Of crustacean remains, a small ostracod — Entomis 

 ( ? ) has alone been found. Plant remains in an unidentifiable 

 condition occur frequentlv. The included limestone bands 

 represent accumulations of enormous numbers of the small 

 tapering pterepod tubes known as Stvliolina fissurella 

 (Hall). To the unaided eye the limestone has a compact 

 appearance, with indications of a finely crystalline texture 

 on the broken surfaces. Viewed under a magnifier, the rock 

 appears finely crystalline, and if sufficiently magnified, is 

 seen to be made up of the very fine delicate needle-like shells. 

 Occasionally these are large enough to be clearly visible 

 under an ordinary magnifier, or even to the naked eye. 

 Most commonly, however, a considerable magnification is 

 needed to show the shells clearly. 



