320 
GEOLOGY OF THE FIRST DISTRICT. 
The rocks of this division may be examined minutely in very numerous localities, but 
slight examinations only of them have been made in the First district, in consequence of 
their not exhibiting so many prominent points of economical or scientific interest as some of 
the others. 
Near Port Jervis, on the Delaware, and thence to Ellenville, the rocks of this division 
are more highly indurated than in most other places, and seem almost trappean in some loca¬ 
lities.t 
Some of the strata can be well examined on the Sandberg creek, one and a half miles west 
of Red bridge, on the line between Sullivan and Ulster counties. It is one of the few locali¬ 
ties where fossils were observed to be abundant. Avicula cliemungensis (Vanuxum), A. tri- 
costata{Y.), A.jlahella (V.j, Cypricardita cliemungensis iY.), Deltliyris prolata {Y.), 
were found in the rocks on the Sandberg creek. 
The rocks can be well examined by following up the valleys of the Good Beerkill, west of 
Ellenville ; the Rondout, west of where it enters the M amakating valley ; the Mombocker- 
kill, in Rochester ; the Esopus, northwest of its junction with the Mamakating valley in 
Marbletown; the Saghkill, in Kingston ; and the Plattekill in Saugerties. These localities 
are in Ulster county. The Marcellus shales are rarely seen in the valleys of the streams 
alluded to, as it is mostly covered by the alluvial and quaternary deposits of the valley. 
Concretionary iron ore, but very impure, was observed in the rock near Ellenville and Wa- 
warsing. 
In Greene county, the strata above the Marcellus shales are well exposed in the ravine 
along which the small stream flows from the west, near the turnpike leading from Catskill to 
the Mountain House. The strata exposed in this ravine are embraced in No. 132 on the 
detailed section^; from the south mountain, to the stone bridge across the Kaaterskill.^ They 
may also be seen along the banks of the Catskill creek, from Madison to Cairo ; and on the Po- 
* Vide section, pp. 303, 315, of this volume — Chapter IV. Catskill Division. 
t A beautiful section of the rocks is exposed to view along the line of the Delaware and Hudson canal, in the valley of the 
Delaware, between the mouth of Lackawaxen creek and Port Jervis. In passing east-southeast along this route, the observer is 
continually descending in the geological series, until he arrives at the primary rocks of the Pochunk mountains. Within a 
quarter of a mile of Port Jervis, the rocks of the Erie division become very dark colored gritty slates of great weight, very sili¬ 
ceous and compact, so as in some instances to resemble some varieties of trappean rocks. 
There are several reasons to induce an examination in detail of this vicinity by those who may have the necessary acquire¬ 
ments and opportunity, viz: 
1. The apparent action of heat on some of the strata. 
2. The neighboring local derangements of the strata. 
3. The mural escarpments on the southern sides of the upheaved hills. 
4. The probability of its being a continuation of one of the transverse lines of disturbance crossing the Highland mountains, 
and extending westward across the white metamorphic limestone region of Orange county. 
The time employed on the geological survey, was necessarily so much occupied in economical geology, to satisfy individuals 
and public opinion, that the great problems of physical geology capable of solution, and some of which might, perhaps, have 
been solved by pursuing a different course, remain for future investigation. 
t Vide the section, p. 303 to 305 of this volume. 
§This is sometimes spelled Caterskill, and Katerskill, but the other is most common. 
