HELDERBERG DIVISION. 
345 
(b) . The middle subdivision is a slaty limestone, containing a great number of individuals 
of many genera and species of testacea, corallines and encrini, and some trilobean crustaceas. 
Some species of the Pentamerus are characteristic. This rock is quarried in many places for 
stone walls, for which it is well adapted, splitting out in layers from an inch to half a foot 
thick; and the stone fences of this rock show a multitude of fossils and of great variety, washed 
clean by the rain, and ready for the collector to have the best opportunity for selection. This 
rock is coextensive with the former, and may be seen along its outcrop in very many places 
in Schoharie, Albany, Greene and Ulster counties, and at Becraft’s mountain near Hudson, 
Columbia county. The best localities I have seen are one and a half miles north of Clarks¬ 
ville, and one mile west of Salem, in Albany county, and on the hills east and west of Scho¬ 
harie. 
(c) . The lower subdivision is a mass of slaty argillo-siliceous limestone, abounding as much 
in fossil remains as the two preceding. The Strophomena rugosa, S. radiata and S', punc- 
tilifera, are perhaps the most abundant fossils. The lithological characters of this rock are 
very different from any of the others in the series, and can scarcely be mistaken if once re¬ 
cognized. It w'as not seen at Schoharie, or west of that place ; but east, on the Helderberg, 
and thence southeast and south to Kingston, it is a prominent, well characterized rock. It is 
the same as the middle limestone of Becraft’s mountain near Hudson. It may be seen near 
Esopus falls ; west of Catskill; near Madison; west of Saugerties ; west of New-Baltimore ; 
one mile north and northwest of Clarksville, &;c. 
Some of the strata of the Catskill shaly limestones afford as beautiful cabinet specimens 
as I have ever seen; even the most minute corallines, of which there are many species, when 
examined by a lens, show their minute pores and markings. 
The Delthyris or Catskill shaly limestone probably contains more fossils, both in genera, 
species and individuals, than any other rock of equal thickness in the State. 
The following fossils found in this limestone, have been described by Mr. Conrad in the 
annual reports, but they form only a small part of its contents. 
Ascidopsis tuberculatus. 
Acantholoma-. 
Crustacea. 
Asaphus pleuroptyx. Dicranurus-, 
— nasutus. 
Corallines. 
Calamopora favosa. 
Delthyris bilobata. 
Testacea. 
Strophomena punctulifera. 
Platyceras ventricosum. 
granulosa. 
macropleura. 
radiata. 
indentata. 
Calceola plicata. 
Conularia quadrisulcata. 
Tentaculites scalaris.* 
gebhardii. 
— pachyoptera. 
Orthis-. 
Strophomena rugosa (depressa). 
Atrypa prisca. 
— inflata. 
— concentrica. 
Geol. 1st Dist. 
* Vide Prof. Vanuxera’s Report, p. 122. 
44 
