ok. Here's something people usually overlook. the very ground or stones in which you walk. one thing about the sidewalks of New York is they have a lot of sparkle or shiny stuff added in the concrete. the reason for that is because the sidewalks are made up of a stone called Manhattan Schist.

A Schist is a medium grade metamorphic rock which has various minerials such as micas,chlorite,talc,graphite and other minerials as well. Quartz is sometimes formed from this and is often called qurtz schists. Mainly it is 50% or more of platy and elongated minerials often combined with quartz and feldspars. also it easily brakes up into flakes and slabs. Most schists are Micca but other types are known as well.



It was formed about 450 million years ago which makes it the second oldest of NYC's bedrocks.(the oldest is Fordham gneiss.). Because of this bedrock, skyscrapers can be errected. If the schist is too far below, then skyscrapers are not wise to errect.
The depth of which it can be found anywhere from 18 ft. below Times Square to 260 ft. below Greenwich Village.

It can be identified by it's glittering appearance caused by the white flecks of mica within it.

It's located mainly in lower and upper Manhattan.
Other bedrock formations in NYC are Fordham Gneiss which is found mainly in the Bronx; the Hartland formation from central Manhattan,Bronx,Brooklyn and Queens;
Inwood marble beneath Manhattan and the rivers that surround it; and Staten Island serpentinite which of course is from Staten island.