According to this Mozilla Developer Network, there is no FirefoxDriver from Firefox 47, instead we use Marionette.
I followed the instructions in this link, but it doesn't work as expected. I am using Java, Firefox 47 and Mac OSX Capitan
npm install selenium-webdriver
chmod +x wires
DesiredCapabilities capabilities = DesiredCapabilities.firefox();
Webdriver driver = new FirefoxDriver(capabilities);
org.openqa.selenium.firefox.NotConnectedException: Unable to connect to host 127.0.0.1 on port 7055 after 45000 ms.
I had the same problem and just solved it by updating the Selenium version to
Hope it helps!