Figure: Bedrock Topography of Manhattan.
This figure shows the bedrock depths relative to sea level. The blue parts are where the bedrock is below the sea level and the orange parts where it is above. The deepest bedrock is in the Lower East Side (but that’s not why there are no skyscrapers there). Most of Manhattan island’s bedrock is some form of schist, though marble makes up part of northern Manhattan and East Harlem. Today most skyscrapers rest directly on the bedrock giving them a firm foundation. Click here to see a helicopter tour.
Source: Jason Barr, Dimitris Ntarlagiannis, and Jan Olchowski
[…] Lower Manhattan, in fact, had some of the worst geological conditions in the island. Because the bedrock there is below the waterline, it is covered with wet sand. This required expensive foundation technologies—most notably […]