Q.black moss in my lawn
I am uncertain of what appears to be a black moss in my lawn really is and how best to treat it. Relatively small patches of what appears to be a moss appeared in my lawn last summer. When the lawn is dry, this black area seems to be moist and doesn’t dry out. It does not drag out with a scarifier and although treated for moss last year, it seems resistant. I have attached a couple of images to help identification. Hope they help!

It probably is lawn slime mold. For more information on lawn slime mold and a course of treatment, please visit the following link:
https://www.gardeningknowhow.com/lawn-care/lgen/black-substance-on-lawns.htm