Actually the book says 'sense', but it does indeed say 'inerrarable'. However, you're right that it must be an error: there's no Latin word close enough to derive it from. The only hit for it in Google Books is this passage.
It's a fair stretch to see it as a typo/blunder for 'inenarrable', but I think you're again right—I can't imagine what else it could be. (Ineffable? Ineradicable?) By the way, there's no variant 'inernarrable': that's a scanning error in modern Web copies of Webster 1913. (See its alphabetical order and etymology here.)
semse is a typo here, and it's a pretty safe bet that 'inerrarable' is as well. This is not the kind of word that English generally tolerates.
"Inenarrable" (or its alternate spelling "inernarrable") are legitimate, if somewhat clumsy, words. Meaning 'indescribable'. Lowry would have done everyone a favor if had just used 'indescribable' or 'ineffable'.