I read the Valancourt "Paperbacks from Hell" edition. The introduction helped put both novellas into perspective. They are unique tales of horror about how monsters are made. Both have strong female protagonists who become twisted by the environments they are trapped inside.
The title story (the shorter of the two) is about a young pregnant wife who is trapped underground, her family assuming she ran away. She gives birth and she and her baby survive, but what remains becomes quite monstrous without the cushion of family, comfort or civilisation. When she escapes in an impossible way and returns twenty years later she feels betrayed by those she loves and who loved her. The tale ends in twisted revenge. It's a satisfying story, albeit frequently ridiculous, but that just adds to the reader's sense of WTF?!
The second story "Beauty Is..." is another strange tale, as much dark fantasy as horror. Some of the terms used are hateful and offensive by both 80's and modern standards, but I suspect this is for effect. It certainly made me feel dirty and uncomfortable even glossing over the minds of some of the protagonists. It's told along two timelines, mothers and daughters. The woman Martha is considered a freak but taken care of by the community at large who owe her mother a debt that can never be repaid.(show spoiler)
Elizabeth Engstrom takes us beneath the surface of civilisation and asks us to take a long, hard look in the mirror.