230 



Report of the State Geologist. 



here, and fish scales and plates are sometimes found. Other fossils appear to 

 be very rare in these beds. 



These forty-five feet constitute what has been termed the Lower Black 

 Band of the Portage group, and the contact line between the Portage and 

 Genesee groups is, in this report, assumed to be at the top of the transition 

 shales before mentioned, and at the base of this black band. Directly above 

 theiv are seventy-six feet of bluish or olive, sandy shales and very soft and 

 thinly laminated sandstones with occasional Hags. Both shales and sandstones 

 are almost entirely devoid of traces of life except for the object known as 

 Ju/coides 'jnipliica, and some undeterminable plant remains. Six feet of blue 

 sandstones overlie these barren shales, above which the recurring olive shales 

 are softer and argillaceous. 



This latter bed of shale is seventy feet thick, the lower part nearly barren 

 of fossils, but the upper layers contain in some abundance Oardiomo9'pha 

 suborhiculiti-ix and Ca/rdiola retrostriata, while several species of goniatites and 

 other characteristic forms are common. The composition of the strata changes 

 very frequently in the succeeding 150 feet, and embraces thick and thin blue 

 and grey sandstones and blue, olive, grey and black shales in thin beds. C< >n- 

 cretions and concretionary layers also occur, with one highly concretionary 

 layer of impure limestone about four inches thick. Fossils are fairly 

 abundant in these beds at nearly every horizon, and many new and interest- 

 ing forms have been found in them during the last few years. Near their 

 top is a bed of black shales twenty feet, nine inches thick, known as the 

 Set ond Black Band. Its summit is 287 feet above the base of the group. 



This second black band is overlaid by forty-one feet of olive and bluish 

 grey, soft shales, through which are distributed a few thin flags. The shales 

 contain many fossils, and in some of the sandy layers casts of Goniatites 

 Pattersoni are not infrequent. 



The section thus far described is that exposed in the Snyder, Hartman and 

 Parrish gullies and the escarpment at the foot of Hatch hill. The measure- 

 ments for the remainder of the Portage strata were made in the Grimes gully. 

 The lowest rock exposed in this ravine is 375 feet above the base of 

 the Portage strata and is composed of flags or very thin, blue sandstones 

 separated by layers of shale, usually light-blue or olive, sometimes dark, and 

 occasionally black and bituminous. 



Fossils, except plant remains, are exceedingly rare. A very large and 

 exceptionally fine specimen of Lepidodendron. Chemimgense, fifteen feet in 

 length, now in the State Museum at Albany, was taken from one of these thin 



