Hi

I just went to the Patten Lumberman's Museum in Patten, Maine, whichdoes not have a vertical saw, but they do have an excellent collection of tools, equipment, buildings, and information.
http://www.lumbermensmuseum.org/

One thing I got out of the visit was a free handout with a chronology of lumbering in Maine, some of which I will write below. I am going to stray a little from the topic, but not too far:

1634 First water powered Sawmill in Maine
1802 Planer pantent applied for
1814 circular saw patented but not in general use [My understanding is the circular saw was invented in 1777 in England though there could have been a paralell invention by the Shakers in America.]
1820 the first steam powered mill in Bath, Maine
1850 circular saw put into common use, gang saw introduced [this seems late to me]
1846 There were 1500 sawmills in Maine.
1858 Joseph Peavey invented the Peavy Cantdog, an improvement over the swing dingle or swinging bitch as it was sometimes called [a bitch is a log dog with tines rotated 90 degrees from each other]
1890-1900 cross cut saws were introduced for cutting down as well as cutting up. They had been patented in 1861 by Canadian Jerome Dietrich.
1976 Last log drive in Maine on the Kennebec River

Thank God for Google books. Here is a book which shows later types of saws published in 1905. http://books.google.com/books?id=Q6sJAAA...try+and+joinery

I will add that part of the sawmill legacy is still with us in that there are still deposits of sawdust on river bottoms such as the Damariscotta River.

There have been an estimated 160 tide mills of all sorts along Maine's coast and a few wind mills such as in Port Clyde.

Something to keep in mind is that the circular saw needed more power (more water) so they were not an option everywere. Also, smaller circular saws were used to resaw flitches, deals, etc. even in mills with vertical saws so look for old lumber with the narrow dimension circular sawn and the wide dimension vertically sawn.

Jim