The book ' _The Original Scots Colonists of Early America, 1612-1783_ '' by David Dobson is also available on archive.org. Abbreviations are listed at the beginning of the book, but as you observed, VSP is not there.
However, all those I checked whose entry included a 'VSP' reference arrived in Virginia, so I decided to check whether VSP might stand for Virginia State Papers.
* * *
Volume 1 of the Calendar of Virginia state papers and other manuscripts is also available on archive.org. James Wood appears on page 185 in the:
> List of Rebel Prisoners Imported by Capt: Edw'd TrafFord, in the Elizabeth & Anne, from Liverpole -
.
So, **VSP.1.185** would appear to be _**Calendar of Virginia state papers. Volume 1. Page 185**_.