Sentence:  It is indeed an 'extensive Volume,' of boundless, almost formless contents, a very Sea of Thought; neither calm nor clear, if you will; yet wherein the toughest pearl-diver may dive to his utmost depth, and return not only with sea-wreck but with true <WSD>orients</WSD>. 
Meaning of the word marked with <WSD> tags:  A pearl originating from the Indian region, reputed to be of great brilliance;  any pearl of particular beauty and value. (19th c.)