But I like it (like it)

Everybody knows that buildings need foundations, right? So how did the World Trade Towers come to be built right on the water? Wasn’t the sandy ground by the water too soft?

No. It isn’t sandy ground. Manhattan is essentially a giant rock poking up above sealevel, a stone called Mica Schist. The engineers just bolted the buildings to the rock and went straight up.

The red areas in the map on the right show that Manhattan is largely mica schist, (or Manhattan Schist, in that borough) but if you look at the Bronx the red runs right up under the ClockTower in a narrow red strip all the way to the Cross Bronx Expressway. The map on the left indicates 172nd and Third Avenue. See? It falls right in that narrow red strip of mica schist.

This old photo above from Google street view shows that very intersection with giant outcroppings of the mica schist dominating the corner lot, all part of that red strip on the map. No wonder nothing was built there at first. The cost to dynamite, chip out and haul that rock would be enormous, but the city needed the lot for low income housing. Now compare this empty lot photo with the very first photo at the top. Same intersection, even the light post and the hydrant have not moved.

The solution? Just leave the rock in place and build over it. You can see the same yellow bodega below in the photo above.

The architects poured the concrete all around it…..

...and sometimes set the building right on it.

The brick has to work around it.

Pieces of the stone chip off and litter the sidewalk so I brought a small chip home and photographed it. 

That’s it on the right. The chip on the left is an internet photo of mica schist I found on this geologists site:

http://www.microscopy-uk.org.uk/mag/artnov08macro/Samuels/index.html

These rocks are pretty big. I rolled my bicycle into the picture for a sense of scale. 

I know, it’s only rock and roll but I like it,

 (like it) yes I do!