The Early Novels Database (END) is hosted by the University of Pennsylvania Rare Book and Manuscript Library (PU), and under development by staff and students at the library, Swarthmore College and the University of Pennsylvania. The project has a stated aim of restoring metadata lost in digitisation projects. If this were actually the case then the six-year old project would have to be considered a failure, even in its "Under Construction" form. It is clear, however, that the actual aim of END is to involve undergraduate students in the collection of detailed paratextual information, annotation, marginalia etc. from the "extensive collection of fiction in English published between 1660 and 1830" available at PU. (A 2011 overview of the project is here.)
I am not sure how I have managed to not hear about the project, given that I am interested in annotation, marginalia etc., particularly that in works by Haywood. But once I did hear about it I realised that it was very likely that END included information about works by Haywood, since PU has a large number of books by Haywood. (With 45 items, it has the fifth largest Haywood collection in the States: larger than that at Yale, Princeton, the Clark.) Unfortunately, it is presently impossible to search END for works by Haywood. On the splash page, a visitor is given the choice of sorting results by title or year (not author), or to "narrow results" by browsing "Narrative form," "Author claim type," "Author gender claim" (by which they seem to mean "Author sex claim"), "Person" etc. Since there was no way to narrow results by author, I did what I have had to do so many times, I simply searched through every single title to identify those by Haywood. It is a tedious way of searching, and would have been largely unnecessary if the metadata in the PU library catalogue had been carried over, but it is effective. Below is the list of titles, arranged chronologically.
The busy-body (1742) *
Memoirs of an unfortunate young nobleman (1743) *
Secret histories, novels, and poems (1745)
The fortunate foundlings (Dublin, 1745)
The adventures of Natura (1748)
Dalinda: or, the double mariage [sic] (1749) *
The busy body (Dublin 1770)
The distressed orphan (1770) *
The female spectator (1771) *
The invisibe [sic] spy (1773) †
The female spectator (1775)
Epistles for ladies (1776) †
The Sopha (1781) †
The history of Miss Betsy Thoughtless (1783)
There appear to be many cases where there are multiple entries for the one work, and there are three records that are empty—links that lead to a blank page (marked † above). Also, only five of the fourteen entries record marginalia or inscriptions (marked * above) of any kind, and most of these provide few useful details. In almost all cases Haywood listed as a “Person” in the primary record, but no linking is provided to her as a Person. The only case where you can navigate from one Haywood work to another is Secret histories, novels, and poems (1745) which links to The female spectator (1771).
Since I examined all of these books late in July 1997, I am not relying on END for my knowledge of the PU colection. But there are a lot of smaller libraries that I did not visit and it would be helpful if projects like this were more common. Involving undergraduates in cataloguing weird and interesting copy-specific information is a great idea. It is a shame that the basic database structure is not better adapted to searching by author since the vast majority of interest in marginalia is focussed on the annotator (as author) or on the annotations (as a response to an author): i.e., it is ultimately a biographical interest.
The only blog entry (on the END blog) concerning marginalia is this one from 2013. In her reflections on Marginalia, Christina Aruffo explains why "marginalia cataloguing can be sporadic"—even in a project such as this—because cataloguing it can be time consuming, cataloguers have their own "accepted and internalized definition of what marginalia actually is"—meaning doodles and library markings ("library marginalia") get less attention than text, as does anything else that cannot be easily related to the text as text.
For student projects based on END data and texts, see here; for papers, see this (including one by Andrew Piper and Ehsan Arabnejad which "draws on a taxonomy of eighteenth-century novels’ footnotes to advance a simple but consequential argument: despite the claims of almost all scholarship on the subject, footnotes in novels were common and referential rather than exceptional and self-referential, meta-fictional, or “postmodern” avant la letter." Nice.)