 There he found letters, notebooks, catalogues, and most pertinent of all , an early draft of Locke's "An Essay Concerning Human Understanding", hitherto presumed missing.
<coherence>  There he found letters, notebooks, catalogues, and most pertinent of all , an early draft of Locke's "An Essay Concerning Human Understanding", hitherto presumed missing.
 There he found letters, notebooks, catalogues, and most pertinently , an early draft of Locke's "An Essay Concerning Human Understanding", hitherto presumed missing.