Verbal irony is easy to point out in "The Interlopers" one example is,"'For forms sake I shall send my condolences to your family.'" This, to me, is considered verbal irony. These two characters at the time hated each other with a passion. It is very likely the man who said this was using sarcasm when he said this statement, meaning he would actually not really care if he died. Sarcasm is a form of verbal irony.
Situational Irony is when one thing is expected to happen, but a completely opposite situation happens. This kind of irony occurs many times in "The Interlopers" for example,"The roebuck,which usually kept quiet in the sheltered hollows during a storm-wind were running like driven things to-night..." This is a strong example of situational irony because you expect for all to be quiet and these creatures to be quiet, but they are the complete opposite of what you expect.
This type of irony is when the audience knows something the characters don't know. This happens in "The Interlopers", for example,for each knew that it might be long before his men would seek him out or find him; it was a bare matter of chance which party would arrive first on the scene." The characters both have no idea that the other's men aren't coming, they both think that the other person's men will get there before his. We the audience know that no men are coming at all and that they are both trapped.