Happy to (very belatedly) back up the Panther's opinion that the Baskerville art is by Mike Sekowsky, after a childhood seeing his work on the early issues of DC's JLA, I can only wholeheartedly concur, irrespective of who may have inked it. Sadly I have yet to see an artist who can really bring Holmes alive on the comic page, and Sekowsky's no exception. I can't name the artist on the second feature, but I find it no more exciting than the first. Oh Lord haven't I been spoilt! :-)
Link to the book:
Super Detective Library 078 - Sherlock Holmes and the Hound of the Baskervilles