One If By Land, Two If By Sea - Which Was It??

On this day (April 18th) in 1775, Paul Revere signalled from the Old North Church (via the church's sexton) that the British were coming. Well, which was it? By land or by sea?

I didn't know either, but you can find out by going the the Old North Church's website. The next days' events marked the beginning of the Revolutionary War. April 19th was (until 1969) remembered as Patriots' Day.