William Mather performed the first New York State geological survey in the 1800s.
In the early 1900s, Veatch worked on Long Island geology. This served as the basis for Myron Fuller's work that was published as U.S.G.S. professional paper 82 in 1914.
Lake Ronkonkoma is 70 feet deep and Fuller(1914) established it as the type locality for glacial kettels. However, it may be that the lake's geological history is more complex than the process described for the formation of kettles, wherby a standed partially buries block of glacial ice melts, leaving a depression. A deep depression exists in the surface of the Cretaceous material beneath the glacial material on which Lake Ronkonkoma has formed. It may be a disrupted drainage system.
Another example of an interpretation of Long Island geology by Fuller that needs to be reconsidered involves the Gardiners Clay. The type locality, on Gardiners Island, is highly contorted, due to glacial tectonics. Outcrops of Gardiners Clay are difficult to find, and many clays that have been identified by other geologists as Gardiners seem to be essentiallly unrelated to it.
In addition, mant features, such as certain depressions, that Fuller interpreted as having been formed by primary, or glacial ice, may actually have been formed by permafrost, or secondary ice.
In colonial times, people were already aware of the existence of kettles, although they did not assign them a geological interpretation. "The "Kettle of York" in Smithtown is a place where colonists used to hide cattle form the British. The farmers used to tell the British that the cattle were in the Kettle of York, and the British believed that this meant that they had been sent to New York City.
Kame and kettle topography refers to hilly morainal areas wher the kettles form depressions and the kames form the hills. Kames are constructional features, in some ways like deltas, that were formed by running water that carried sediemnt within the glacier. Where the water fell into a crack or off the edge of the ice, it dropped its load of sediment, forming a deposit next to the ice. After the ice melted, this deposit remained as a mound. Being glaciofluvial in origin, kames are stratified. Kame moraines mark the edge of the ice. In fact, the moraines of Long Island are primarily glaciofluvial rather than till. This is in contradiction to the mistaken impression that some people have that the moraines are composed mostly of till. Glacial sediment, including both till and glaciofluvial deposits, is collectively know as glacial drift.
Bald Hill is a huge kame on eastern Long Island.
Excavations of a postulated kame on Shelter Island by Steve Englebright indicate that its surface is composed of stratified sediments draped over its top. They seem to dip away from the summit on every side of the hill. This is what Fuller would have expected a kame to show.
Although till usually exhibits no internal stratification, partial melting of ice mixed with sediment can cause flow and deposition that results in layering. This forms a flow till.
Outwash is deposited in cold climate alluvial fans called sandurs. As is evident on topographic maps of the south shore of Long Island, they grew laterally into one another to form the Hempstead Outwash Plain. North of the Hempstead Outwash Plain is the Ronkonkoma Terminal Moraine. Together, these two features form a geomorphic couplet.
North of this lies another geomorphic couplet composed of the Terryville Outwash Plain and the Harbor Hill Moraine. The Harbor Hill Moraine lies adjacent to the north shore along most of the length of Long Island, with the Terryville outwash plain lying between the two moraines. Harbor Hill next to Hempstead Harbor serves as the type locality for the Harbor Hill Moraine. The islands of Peconic Bay seem to be part of another moraine, referred to as the Peconic Bay Moraine.
The barrier beaches of Long Island's South Shore form yet another geomorphic feature.
Geologist Les Sirkin is a classic splitter. He has proposed a proliferation of names for different parts of Long Island's moraines. For instance, the Stony Brook Moraine and the Roanoke Point Moraine are both part of what others refer to as the Harbor Hill Moraine.
Les Sirkin is a palynologist. Palynologists study pollen, which reveals information about past climate.
Sirkin recognizes the following past vegetation associations on Long Island:
Fuller interpreted the Mannetto Gravel, which lies on the boundary between Nassau and Suffolk Counties, as the oldest glacial formation on Long Island. However, it may simply be weathered outwash. It is possible that the material has been involved in multiple glaciations. Sirkin believes the weathering occurred in proximity to ice lobes. The granite in the Mannetto Gravel is "rotten" due to the weathering, however it may have occurred. It easily crumbles when it is squeezed by hand.
The glacial ice does appear to have formed lobes. Obstructions slowed the ice movement in some places, while low areas, such as the Hudson and Connecticut Valleys, allowed it to move more quickly. Lobes formed along the ice fornt where it moved relatively quickly. Shelter Island, which is shaped like two chevrons, may have been formed in an interlobate zone.
Loess is wind-deposited silt that forms thick deposits along the North Shore on eastern of Long Island. In China, loess is very thick and people can build cities by excavating it because it can hold up wel without collapsing, except when earthquakes occur. When this happens, the result can be disastrous.
Silt can fillin spaces between larger particles in till. This makes it able to hold moisture much more effectively than sand and gravel, which characterize outwash. Because it strongly influences moisture content, the amount of silt can help explain the vegetation. The Dwarf Pine Plains is a biological response to drought.
The moraines contain substantial amounts of pre-advance outwash. The glacier advanced over this pre-advance outwash. It can distort it in the process.
Basal till is compressed and dense, while meltdown till is lighter. Basal till almost seems lithified.
Glaciofluvial deposits make up the area wher the Smithtown landfill was established. These deposits show nice foreset beds that formed as the meltwater entered satnding water. The Smithtown Clay formed in a glacial lake. The glaciofluvial deposits in Smithtown show channel deposits on top.
The type locality of the Terryville Outwash Plain is near the South Setauket Pine Barrens, which are underlain by glaciofluvial deposits. A nearby delta deposit is evident in a gravel quarry in Setauket.