in the hound of baskervilles, does it say what kind of dog it is, or just "mixed breed"?

Answer 1

Well, the dog at first was considered a legend, and was described as a "hound of hell." But the dog that actually appears is most often described as a "hound:"

"It was not a pure bloodhound and it
was not a pure mastiff; but it appeared to be a combination of
the two"

Answer 2

Look in spark notes