Thomaston Ct, Near the River

First time sighting, Was driving just off of S.Main St to a lot leading close to the river. I saw an animal (thought to be a bobcat at first). It turned back towards the tree line as soon as I had my first sighting and was approaching from about 50 yrds away with my noisy diesil. It appeared to the size of a larger dog, with a dark tipped tail. Saw it and then it was gone in about 2 seconds. Never seen anything like it before.