What I could see was the main part of his body nestled in the grass - it looked very much as if he had the front part of his body going down an unseen hole in the ground - he was motionless and I just waited - knowing that the hiss I heard was a good indicator that his head-end was not in the ground but lurking in the grass. Eventualy I saw his head - I think only because he lifted it to get a better look at me

We stared each other down for a minute or two, both of us motionless. I then ventured closer to try and capture his portrait -

I kept my distance and eventualy he started slowly to make for safety, flicking his tongue to taste the air and keeping a beady eye on me all the time. In the next picture you can see almost the whole length of the beast - I estimate him to be somewhere north of 4 foot in length. Notice that here he is in "travelling configuration" - fairly well stretched out with only enough sinuosity to allow him a purchase on the terrain to make progress.

All this time the dog hadn't noticed him - unusual because the dog in question has demonstrated a very fine nose. But the snake must have been close to odorless, because the dog went bounding by unaware that he had nearly trodden on the snake. But the reaction of the snake was instantaneous. He whipped round to face the source of danger and contracted the length of his body concertina-fashion, the better to be able to launch a strike if necessary. This was accompanied by a series of surprisingly loud hisses. The dog continued on his way, blissfully unaware of anything unusual.

But fright caused by the dog apparently broke the snake's trust in me. Even though the dog was well away and the snake could have resumed his journey to safety with impunity, the snake instead opted to maintain his strike configuration and face me.

Notice how well camouflaged are the snake's eyes in this picture (If you can't see them immediately, look closely at the dark brown band that encircles his snout - they are in there.)

As best I can determine, this critter is the common Gopher Snake (Pituophis melanoleucus) His coloration is designed to mimic a Rattle Snake and he can even flare out his cheeks to resemble the diamond-shaped head of a rattler. There is also a variant living nearby (which I encountered in my driveway some years ago) who has developed some rudimentary rattles on his tail. These he will shake at you in the hope of convincing you that he is a lot more dangerous than he really is. But I could see no sign of these rattles on the snake pictured above. Full-grown Gopher Sakes can range from 4ft. to 8 ft in length it says on the web...

After a wary stand off lasting a few minutes, I moved away and watched from a distance. The snake remained motionless and in strike configuration for a few more minutes. Then eventually he slithered off in the direction of the creek.