Geomorphology with Old Bottles

Five days ago, I retrieved a bottle from a steep bank in the salt marsh. After cleaning it, I was able to get a rough date on it - before 1920 and maybe the last half of the 19th century. Large air bubbles in the thick green glass put it before 1920. It had been closed with cork, the neck was bulged by design, the top was slightly deformed in the manufacturing, and the bottle had no embossed lettering or makers marks. Most likely, it was a beer or liquor bottle. Now, there was a second bottle sticking out of the bank at about the same level. With the low tide, I could not reach it, so I returned today timing my trip for a tide that was six or eight inches higher. I just had to find the same spot.

 

First bottle in center, second bottle above the bow of the canoe -Aug 22

 

The location was a inlet leading off of Nell's Channel. While I did not record the location, I did remember what it looked like. When I got down to the channel, I just checked each inlet on my left side. It was farther than I remembered, but the steep sides on the inlets left side made it obvious.  There was the bottle. I took compass bearings this time. 260 deg to the Bridgeport smoke stack, 015 degrees to the Milford smoke stack.

The bottle is 27-28 inches down from the top

Multi-sided, machine made, early screw top, clear glass

This bottle had a makers mark on the bottom - a simple capital F, and a mold number at the base - 486.
Dating the bottle was easy. It is a catsup bottle made by Owens between 1905-1916.

If you need to know more about bottle dating, try this site. It was originally hosted by the Bureau of Land Management. Suffice to say, it has enough detail for any archaeologist.
https://sha.org/bottle/dating.htm

There is no archaeological context for bottles found in the center of this marsh (or I would not touch it). No one ever built anything here - the bottles could have floated in on the tide from Long Island Sound, or they could've drifted in on the river, or someone might have just tossed them not too far from where I found them. What is interesting is that they were both about 27 inches below the surface and both bottles were made before 1920. Of course, I don't know when the bottles were actually tossed into the marsh, but it can't be much before 1920. Anyway, I can guess that it took maybe 75-100 years to build up 27 inches of earth in the marsh. Note that there isn't any standard for build up in a salt marsh, in fact, the build-up at this location probably varies from other spots in the same marsh...way too many variables in the process.

One thing I noticed when I first moved here (because I like digging through historic maps and comparing them to current land features) is that the spartina islands in the coastal salt marshes are pretty much the same sizes and shapes as they were in 1900. Another thing that I noticed was that the edges of the islands calve somewhat like glaciers. Not being a geologist, I imagine a situation where the marsh islands continue to gather "fill", either by silt being deposited, or by the deposition of a large annual mass of spartina and other marsh plants. The islands maintain shape by slowly compressing and forcing their edges outward, where they split off (there are often crevasses a few feet from the edge) and calve, with the calved chunks melting away in the river current.

The tide is flooding, and that means the marsh is filling - that curious thing where the current isn't moving upriver, but moving into the center of the marsh from all directions. I float up the "bottle" inlet and find it going very much farther than I expected. 

With the tide coming in, if I ground out, I only have to wait for a few minutes to continue. But, I wander around and eventually find my way to Milford Point. 

Juvenile Night Heron

There are lots of Snowy Egrets and juvenile Night Herons. A few Great Egrets, a few Great Blue Herons, and the Osprey are busy hunting. I circle the marsh and ride the flood current up river to my take out.