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NEW YORK STATE MUSEUM 



Among gastropods the close coiled and extremely rotund 

 Diaphorostoma ventricosa [fig. 90] and Stroph- 

 ostylus expansns [fig. 91] are the most characteristic. 

 A number of species of Platyceras also occurs, P . nodosum 

 [fig. 92] being the most striking. 



Esopus shales 



Cauda galli grit, cocktail grit 



Besting on the wave-marked surface of the upper quartzite bed 

 of the Oriskany of this region we find a dark brown or black 

 silicious or gritty shale of very uniform character and virtually 

 barren of organic remains. This formation is well exposed in the 

 Esopus creek below Saugerties, from which locality it derives its 

 name. Throughout the Helderberg region it maintains a very uni- 

 form character, commonly splitting into small rectangular frag- 

 ments, which cover the slopes of the hillside underlain by it. In 

 the disturbed region south of Saugerties this formation is strongly 

 affected by slaty cleavage, which entirely obliterates all traces of 

 the original bedding, but in the Schoharie region the bedding is 

 readily discernible, specially in fresh exposures of the rock. 



There are few exposures of this formation in the Schoharie 

 region, the only opportunity of seeing the lower beds being where 

 artificial excavations have been made. Such an excavation is 

 seen occurring on East hill, on the road which ascends the hill 

 northeast of Schoharie, near Avhere it passes from the Becraft 

 onto the Oriskany [see map]. As usual a brief exposure has 

 caused the checking of this rock so that it is mainly a slope of 

 loose material. Near the summit however along the line of con- 

 tad with the Schoharie and Onondaga beds, large slabs are often 

 found covered with the peculiar markings which, on the supposi- 

 t ion that they were seaweeds and owing to the fancied resemblance 

 of the marking as a whole to a rooster's tail, have been named 

 Spirophyton (Taonurus) c a u d a - g a 1 1 i [fig. 93] . 

 Prom this structure the rock has received the early name of 

 ( !auda-galli grit. It is highly probable however that the structure 

 in questioD is inorganic, representing wave-marks of a peculiar 



