We were recently sent this image of an oil painter by its owner, who is keen to find out more about its origin and subject.
The painting dates from c. 1775-1800, and may represent a location in Wales or the Alps. Identification of the site may lead to an identification of the artist – please get in touch via the comments below if you have any thoughts!
Geological Society of London blog 
I just had an epiphany of who this might be by after seeing it in the summer. I’m pretty sure this is by Richard Wilson, a prominent Welsh landscape painter during the Victorian Era. Here’s a page about him from the national gallery: https://www.nationalgallery.org.uk/artists/richard-wilson
Hope this helps.
Regards,
Chase