I have a stack of postal cards, between 1800s and early 1900s that I have been going through...

I have seen the "cut squares" (is that right?), of the corners of the old postal cards and envelopes but I'm thinking since my grandfathers left these together maybe there was a reason for it, because it IS some interesting things in the correspondence and postmarks and whatnot beyond that square. Is it right to leave them whole?
Also, of the stack, these 2 stood out as being different than the others, does anyone know much about them?
This one was interesting because although I have similar cards, this is only one with rounded corners. I don't know if it came like that or if the bank that mailed it did it...


This one I don't have any quite as fancy that are red or with this picture...


Thanks again everyone! I was struggling by myself on this journey, you all make it a lot more enjoyable!
