Growing Buildings: The Placement of Early New York City Skyscrapers
The presence of bedrock below Manhattan's surface influenced the placement of buildings across the city. To securely construct buildings, they need to be anchored to bedrock, or else they will not be stable. Therefore, it is important to build in places where bedrock is easily accessible.
In certain places across Manhattan, the demand for skyscrapers was high, but the access to bedrock was limited because it was deep below the surface, so it was hard to get to. Aside from this, there was also the problem of variations in the topsoil throughout different areas of Manhattan causing inconsistencies in the way buildings could be built and, furthermore, the problem of subterranean rivers causing topsoil to become muddy and unstable. These places might have had a high land value, but building there would be impractical, as there would be no easy way to stabilize buildings. There were some places in lower Manhattan, however, that were more practical to build upon. In Manhattan, “across the island as a whole, access to bedrock varies greatly... this access [to bedrock] affected the pattern of skyscrapers we see today.”
In the graph shown, the correlation between skyscraper placement in Manhattan and the proximity of bedrock to surface level can be seen. In areas where bedrock is closest to surface level, such as the area around City Hall, there is a higher presence of skyscrapers. While the distribution of bedrock across Manhattan might not have influenced where the business districts themselves are, it influenced the local placement of skyscrapers within the districts. Furthermore, it also influenced the placement of skyscrapers within the Manhattan skyline, since many of the buildings in the skyline were built on one of these pockets of bedrock. An example of a prominent building from the Manhattan skyline that was built on one of these areas is the Woolworth building.
In order for skyscrapers to be structurally sound, they, along with any other buildings, need to be anchored to bedrock, a solid rock that underlies looser deposits of topsoil. Without being anchored to bedrock, buildings settle over time, causing them to become uneven and unsound. Therefore, buildings always need to be anchored to bedrock. The problem with anchoring buildings to bedrock, however, is the expense – if bedrock isn't already near surface level, cost can be prohibitive. An excavation process must be initiated to reach the bedrock buried within the earth if it isn't already near surface level. This process is expensive and time consuming; it is easier to just build on locations where bedrock is already near the surface. Consequently, since it is easier to build on areas where bedrock is close to surface level, this is where many buildings ended up being constructed. Since buildings were built more heavily on these areas, they became concentrated. Many buildings were constructed on a small amount of land, increasing the density of buildings per unit of land. This density is reflected in the Manhattan skyline, which becomes dominated by buildings.
In lower Manhattan, bedrock, mostly a strong metamorphic rock referred to as Manhattan schist, lies within several feet of the surface of the earth. This bedrock was relatively easy to access, and thus relatively easy to build upon. After all, skyscrapers, as well as other buildings, were not necessarily built where bedrock was the deepest, but where it was closest to the surface. Tassier argues that it is “in the very lower part of Manhattan (from Wall Street south) we would expect to see skyscrapers since the rents are extremely high and the bedrock is not too far from the surface,” and he is right; we do see skyscrapers there. It's until we move farther away from that point that the amount, and heights, of buildings lessen. This is reflected in the Manhattan skyline. Many of the buildings seen along the Manhattan skyline were built where there is a strong presence of bedrock close to surface level. As seen in the geologic map of New York City here, there is a large amount of Manhattan schist on or around the area that the buildings of the Manhattan skyline were constructed on.
An important contributor to the heights of buildings regarding building placement is land appraisal value. Contractors want their buildings to be immediately accessible to the general public. The closer buildings are to public transportation, the more likely it is that they will generate revenue. Generating revenue is important because many skyscrapers were built on land with a high appraisal value. As the values of land increase, “holding square footage or volume constant, builders have an incentive to build a taller building on less land instead of a shorter building on more land.” Building in this manner creates a vertical landscape, rather than a horizontal landscape. Essentially, by building in this fashion, contractors are getting more square footage of building space for the same amount of money. Otherwise, if builders were to build short buildings on a piece of land with a high value, they would be spending a lot more money on less of a final product. This way, “skyscrapers are more likely [to be built] when land values are high,” which is one of the reasons that the Manhattan skyline eventually came to be dominated by so many tall buildings.
 An example of an early skyscraper in New York City is the New York Tribune Building, which was built in 1875. This 260 ft. building was located on Park Row before it was demolished in 1966.
“Tribune Building, 154 Printing House Square, Nassau & Spruce Streets, New York, New York County, N,.” Historic American Buildings, 1888, Still image.
 The current Lower Manhattan skyline. This skyline is constructed of multiple buildings, many of which are skyscrapers. One of these is the One World Trade Center. One WTC is currently the tallest building in the Lower Manhattan skyline, measuring at 1,776 ft. Construction of the One WTC began in 2006, making it a more recent addition to the skyline.
“New York Skyline Cam,” EarthCam, 2014. http://www.earthcam.com/usa/newyork/skyline/?cam=skyline_g.
"One World Trade Center." World Trade Center, Silverstein Properties. 2014. http://www.wtc.com/about/freedom-tower."
 Barr, Tassier, & Trendafilov. "Bedrock Depth and the Formation of the Manhattan Skyline, 1890-1915." Discussion paper series, Bronx, New York, 2010., 2.
 There is a popular myth that states that the reason Manhattan’s two business centers developed in downtown and midtown is because of the large quantity of bedrock below surface level; however, this isn't particularly true. While bedrock is an important factor to consider when constructing buildings, particularly tall ones such as skyscrapers, it is the proximity of bedrock to surface level that is important, not necessarily the amount of bedrock that there is. In addition to the amount of bedrock below the surface, there are several other factors that are argued to have influenced the placement of buildings as well, such as high income versus low income geographic distribution.
 Ibid, 3.
 Depths (as measured relative to the surface) of bedrock in Manhattan, south of Central Park.
 Ibid, 4.
 For many years, the Woolworth building was one of the major components of the Manhattan skyline. The Woolworth is just one example of a building that was constructed on an area where bedrock is close to the surface.
“Brooklyn Bridge, East River and the skyline,” Detroit Publishing Company, 1915, dry plate glass negative.
 Anchoring a building to bedrock is the process of casting or setting a building's structural frame to its bedrock foundation, which both stabilizes the building and prevents it from moving.
Conrad, Mackie. “Starting off on the Right Foot: How to Properly Anchor Your Building.” Prefab Metal Buildings, 2014.http://www.buildingsguide.com.
 Barr, Tassier, & Trendafilov. "Bedrock Depth and the Formation of the Manhattan Skyline,” 1.
 Ibid, 10.
 Ibid, 14.
 Geologic map of New York City showing the various different presences of rock below the surface.
“Geologic Map of New York City.” New York: Stony Brook, October 2001.
 Barr, Tassier, & Trendafilov. "Bedrock Depth and the Formation of the Manhattan Skyline,” 14.