I can date this first group of slides as being later than 1955, since they were mailed to the 5th Avenue South address, but beyond that, they were unmarked. But there are some great shots here, mostly of scenes in Glacier National Park, beginning with these two of St. Mary Lake:
Here are three more lovely shots, presumeably also in Glacier, but of scenes I can't identify:
Here are three photos with highway included, giving you an idea of the kinds of views Glacier offers without even leaving the comfort of your vehicle:
Here is another, showing part of a structure; I think it might be near Logan Pass:
A more imposing structure is in this photo; it's Many Glacier Hotel, where we never stayed overnight, but where we visited often and probably had some meals. In 2014, we realized a dream and actually spent a night at this wonderful hotel. You can read about it and see more photos here. Below is a shot of Steve, Joan, and I on the hotel's deck just after sunset.
Here a couple of scary-looking blizzard photos, taken at an unknown location.....
...... and a photo of a lovely, unlabelled, mountain stream:
This next small group was also undated, but with some pictures of people that made it clear they were from much later in our stay in Montana. They look very much like the Tetons, so they must have been taken on one of our Montana-Texas trips: