10 
GEOLOGY OF THE FIRST DISTRICT. 
Constitution island and Gouverneur’s landing, opposite West-Point, and between Constitution 
island and Coldspring * 
A large portion of the low lands along the rivers, creeks and smaller streams, which are so 
generally celebrated for their fertility, and which vary in texture from clay through loam and 
sand, to gravel and pebble beds, belong also to fluviatile alluvions. The most extensive depo¬ 
sits of this class, are those on the Walkill, extending from below Springtown, by that village 
and New-Paltz, to near Libertyville; those of the Rondout river, near Rochester, Wawarsing 
and Ellenville ; those of the Esopus creek, from Marbletown, by Hurley and Kingston, to near 
the Esopus falls ; those of the Catskill and Katerskill creeks; and the Schoharie flats, which 
extend, with slight interruptions, from the mouth of Kripplebush kill, by the villages of Cen¬ 
tral-bridge, Schoharie and Middleburgh-bridge, to four or five miles above the latter place. 
Lacustrine and Marsh Alluvions. 
These are formed by the combined effects of the growth and decay of organic matter, and 
the deposits of the waters from the adjacent country flowing through them. The nature of 
the materials forming these alluvions varies much, according to local causes. If the water 
flowing into lakes or marshes with a gentle current be loaded with earthy matter, the ooze (or 
muck, as it is frequently called by our farmers,) will probably predominate. When the soils 
contain much lime, or if calcareous springs occur in the vicinity, fresh water moUusca will 
probably exist in quantities, and cause the deposition of shell marl; if neither of these causes 
should predominate, vegetable matter will accumulate so as to form peat. 
Shell or Lake Marl. This deposit, so very useful on many soils as a manure, is continually 
forming. It is abundant in some parts of the district, more particularly in that which forms the 
valley of the Hudson. It occurs in those ponds, swamps and meadows which are fed by springs 
containing lime, or which serve as receptacles for the surface waters flowing over calcareous 
materials. It is a matter of common notoriety, that shells are very thin, and not abundant, in 
waters containing little calcareous matter. Almost all soils contain a little carbonate, sulphate 
or muriate of lime, some of which is carried by the surface and spring waters into marshes, 
rivers, lakes, etc. The calcareous matter is there absorbed and secreted by the testaceous 
animals, so as to form an external covering for their protection ; but in those situations where 
little calcareous matter is furnished, the shells do not accumulate so as to form shell marl, 
because the testacea of each succeeding generation, in forming their own shells, consume 
those of preexisting ones. 
Where calcareous matter is abundant in water, testaceous animals secrete enough from their 
food to form their shells, without the necessity of consuming the dead ones of preceding gene¬ 
rations, which often accumulate in so great quantities as to form thick and extensive beds of 
*■ In 1822, sloops used to come in at the foundry dock, about half way between Coldspring and the W'est-Point foundry, to 
take in their freight of cannon and other castings; but the water has become so shoal that for some years past it has not been 
possible, and they now load at Coldspring. 
