If they aren't actually subdomains AND don't have their own analytics code then yes, it would effect the bounce rate. You said directory, which is just folder to me. The pages are obviously of interest, is the traffic to them organic? You didn't mention time on page for those poetry pages either.
Another consideration is if they actually dilute the topical value of the "main" site and would do more good going away BUT if they aren't subdomains, what percentage of the total site do they make up (before you cut your site in half)? Rather than move them away or create subdomains, you could try to find creative ways to move those users from page to page and lower the bounce rate.