Dorset Map 18th Century

[Mouse]

Yes. Saying they might be windmills was a bit of a mistake, given that they are in the water

I thought it was marsh, but apparently its mud flats. This is a screen shot from Google Earth showing the Wareham Channel, which has changed course since your map. I've ringed Arne as a point of reference, and drawn a red line along approximately the course of the channel as it is shown on your map. There's nothing there now, but they might have been posts like telegraph poles sunk into the mud to mark the course around the bends that existed in the channel back then. Notice how they only occur around the bends and nowhere else on the otherwise straight channel.

Wareham Channel.JPG

There are similar posts sunk into the mud to indicate the channel for fishing skiffs along the Fleet, nearer where I live. They have a cross or a triangle on top of them and are painted red, black and white - so yes - channel markers

[Corben]

Yes. Saying they might be windmills was a bit of a mistake, given that they are in the water

I thought it was marsh, but apparently its mud flats. This is a screen shot from Google Earth showing the Wareham Channel, which has changed course since your map. I've ringed Arne as a point of reference, and drawn a red line along approximately the course of the channel as it is shown on your map. There's nothing there now, but they might have been posts like telegraph poles sunk into the mud to mark the course around the bends that existed in the channel back then. Notice how they only occur around the bends and nowhere else on the otherwise straight channel.

Wareham Channel.JPG

There are similar posts sunk into the mud to indicate the channel for fishing skiffs along the Fleet, nearer where I live. They have a cross or a triangle on top of them and are painted red, black and white - so yes - channel markers

Yep, I think they're channel markers. Poole Harbour is very shallow. Stray from the channels and you end up stuck in the mud. They must have had lanterns mounted on the top for night-time navigation.

Re your comment about aerial photographs - good tip about 1976. I remember that summer. It was hot. As it happens I have a set of high res b&w survey aerial photos that were taken in the 1940s by the RAF. I've spotted one or two possible cob cottages on the photos that tie up with Isaac Taylor's map.

[Mouse]

If you can use photos that were taken before the bombing raids you can at least rule out all the bomb craters before you start looking for fireplaces

Most of the marks on the Dorset Downs that are visible in aerial photos taken since 1945 are bomb craters, and the Dorset Downs are only a couple of miles away off the west of your map.