How did landforms affect the Brooklyn bridges building?

Building the Brooklyn Bridge near the end of the 1870s was a very difficult task, as the tools were still not powerful enough like nowadays. But this was not the only problem, as the bridge had to overcome a huge distance on the East River between Manhattan and Brooklyn, where the riverbed was very muddy. The first task was to find a solid bedrock for the base of the bridge, but it turned out that it was even deeper than expected, so work was halted for a while for further investigations.