Wooden Square-Bin Grain Elevator
These are the ubiquitous small-town grain elevators. Many that survive are sheathed with iron or steel sheeting to protect the flammable wood from the sparks of steam locomotives (Talbot 1983). The small wooden elevators are often referred to as "country grain elevators" since they usually occur in rural areas or small towns.
The seventh and eighth are two versions of a large wooden elevator on the shoreline in a detail of two 1867 bird's-eye-view maps of Wynona, Wisconsin, available as a zoomable image 1 or image 2 online from the Library of Congress.
The ninth is a medium-sized wooden elevator on a rail line in a detail of a 1867 bird's-eye-view map of Aurora, Illinois, available as a zoomable image online from the Library of Congress.
The tenth is a medium-sized wooden elevator (probably) on a millrace in a detail of a 1867 bird's-eye-view map of Bloomington, Illinois, available as a zoomable image online from the Library of Congress.
The eleventh is (probably) a wooden elevator in an industrial area in a detail of a 1867 bird's-eye-view map of Cairo, Illinois, available as a zoomable image online from the Library of Congress.
[Terminal-Sized] Wooden Grain Elevators (Super-Size Me!)
These are super-sized elevators found at terminal cities, where grain had to be transferred or stored, such as cities on the Great Lakes. By about 1900, wooden construction was rapidly falling out of favor in lieu of concrete and other materials.
The top panorama is a view of the elevator waterfront of Buffalo, New York, sometime in the 1870s. The original image is in the History of Buffalo's Grain Elevators website. The "Brown Elevator" and other Buffalo panoramas are probably from the 1880s-1890s, and from the New York Public Library's Robert N. Dennis Collection of Stereoscopic Views. The last pan is looking northwest from (what was in the 1902 bird's-eye-view of Buffalo) the Anchor Line dockyard, with the Watson Elevater at the left edge, and probably the Bennett and Union elevators in the background.
"Reeds Elevator" was said to be "the most complete elevator in all its appointments in Buffalo," New York, when it opened in 1862. The exterior and the roof wore a fireproof shield of slate. The original image is in the History of Buffalo's Grain Elevators website.
The "C.W.Evans Elevator" replaced the earlier 'Grain Warehouse with Grain Elevator' original Evans Elevator in Buffalo which burned in 1862. (The original image is in the History of Buffalo's Grain Elevators website.) The other Evans image is from the 1902 bird's-eye-view of Buffalo, where the elevator appears to have been added along the cupola and on the side (or replaced; and the neighboring elevator is now also owned by Evans).
The two tinted drawings appear to be a large wooden elevators (the patterns of squares are probably the ends of tie rods) along the Chicago River, in two details of a naively rendered 1857 bird's-eye-view map of Chicago, Illinois, available as a zoomable image online from the Library of Congress.
The arcaded Elevator is the "Sturges Elevator" in Buffalo, New York. The image is from an 1863 bird's-eye-view of Buffalo.
Two subtypes of wooden construction are indistinguishable on the outside:
Square-Bin Grain Elevator [Module] or Annex
or "Permanent Vertical-Crib type Annex" (Inglis)
The wooden secondary buildings in the images appear to a separate, dependant, square-bin unit added to their group to increase capacity to the facility. The lack of a protruding headhouse clerestory/cupola indicates that it is dependant on the other (presumably main) building for its sorting and directing movements. These happen to all be wooden; presumably, there are also steel-panel and steel-frame versions.
Though the term appears to be a part of the vernacular, I hesitate to call this subtype an "annex" since that would be confusing with the "Annex Type Family Grain Elevator."
Masonry Square-Bin Grain Elevator
Steel-Panel Square-Bin Grain Elevator
Factory-made panels of steel sheeting are bolted together to create bins and walls.
Steel-Frame Square-Bin Grain Elevator
This type is less well known, and rarer than the others. It is essentially a short, steel-frame skyscraper, with square vertical bins formed within the steel grid. The walls are usually closed-in with rectangular clay tiles or reinforced concrete, and often the concrete-encased steel frame is left clearly exposed on the outside. The construction is probably relatively expensive for smaller buildings, and so most of this material are probably [Conveyor-Dominant] Grain Elevator Types.
...unless what I've seen are flour mills about which I'm confused ...
Left: A construction photo shows workers atop the cribbing before being sided over (AIA Journal 11/77). Right: An unfortunate demolition exposes the plank cribbing that composed the bins in a grain elevator. 
