What is circulating is a one-page typewritten "ancestry," completely lacking documentation.  Whether the original was a deliberate fraud or merely the work of an inexperienced amature remains unknown, but either way, the result is a pedigree that is altogether unreliable because there are entries ranging from gross mistakes to outright fabrications.

The beginning of the pedigree includes the most serious errors, so I will duplicate and discuss it below, but the format of the entire page is a bit confusing.  This "ancestry" is simply a list of husbands and wives, one or the other of which is a LYON, typewritten on one side of a single piece of paper, with a few interspersed notes.  There is no documentation beyond the name and address of the library where the pedigree was said to be found.  The title and format initially imply that it's a line of descent, but the birthdates of the individuals (some in close succession) make that interpretation impossible.  Only the note beginning "Sons of...", in the part quoted below, makes it clear that the four names listed above it are intended to be read as the sons of the first couple on the list.  Following this note, there is simply a list of successively younger LYON couples, with no indication of the couples' relationships to one another, if any.

• The first alarm is sounded with the given name Glenn.  Glenn/Glen is a relatively "modern" given name.  It appears first in the records as a surname, then as a middle name, and lastly as a given name.  As a given name, it does not become common until the late 1800s and does not appear, at all, as a given name until the late 1600s and early 1700s, and then only very rarely.  I don't believe that such a person as "Glenn LYON" existed, or even could have existed, in the 1500s.  What makes the name all the more suspicious is that a huckster would know that such a name would "sound good" to a naive client because the family tradition is that these LYONs came from Glen Lyon, in Perthshire, Scotland.  And speaking of Perthshire...
• Someone isn't born "at" Perthshire.  Perthshire is a county.  One is born "in" a county.  Furthermore, there is not one shred of evidence, beyond tradition, for the birthplace(s) of Henry, Thomas, or Richard LYON.  We do not know — no one knows — where they were born.  But given that they were moving in the company of Puritans of English origin, I would lay odds that the three were born in England, not Scotland.
• The next alarm bell goes off upon seeing the name of "Sir LYON's" wife as "Lady BOWES."  The Queen Mum of England is a BOWES-LYON, and giving Glenn LYON a wife named BOWES is exactly what a huckster would do to titillate a client wanting to make the connection to the Queen's bloodline.  The BOWES-LYON connection was not made in the Queen Mum's lineage until John LYON, 9th Earl of Strathmore, married Mary Eleanor BOWES in 1767, so a BOWES-LYON connection in the 1500s is immediately dubious.  It is just too neat, too cute, and too convenient — and I have found no evidence that "Lady Priscilla" existed. 
• Henry, Thomas, and Richard have long been erroneously assumed to be brothers, but Y-DNA testing shows that only Henry and Richard are related.  In any case, and as far as I know, not one of them has ever occurred in the records with the middle initial "B."  Our perpetrator appears to have given the three this middle initial intending to imply that their middle name was Bowes, thus lending support for their connection to the Queen Mum, in addition to their being brothers.
• The fourth brother, Bowes G. LYON, is another alarm bell, again because it points to the desired connection with BOWES-LYON and the Queen Mum (I presume the middle initial, "G.," was manufactured to support the connection to "Sir Glenn.")  I have found no evidence for the existence of any Bowes LYON, much less this one.
• The wives of Thomas and Henry LYON are securely known, and they are not the women given above (see their family group sheets, linked here to their names, which were based on Torrey, 1997, and additional evidence).  Thomas LYON married first Martha WINTHROP and second Mary HOYT.  Henry LYON married first Elizabeth BATEMAN and second Mary __?__.  But even if we did not know who Henry's wives were, the name given above would be suspicious because O'HALORAN is an Irish surname and the holder would most likely have been Catholic.  I can hardly imagine a New England Puritan marrying a Catholic, especially a Puritan so ardent that he joined the colonists at Milford, who had left Massachusetts and gone to Connecticut to found a more "religiously pure" colony, and who then left Connecticut for New Jersey to found another new colony for the same reason.  Also, there appear to have been no O'HALORANs in New England prior to 1700, for there are no O'HALORAN marriages in Torrey (1997), which is a compilation of very nearly every documented, pre-1700 marriage in New England (over 100,000 individuals).  Neither is there an O'HALORAN in the massive compilation by Savage (1860-62).  Nor, by the way, are there any CAMERONs, WAYNEs, or MARQUETTs in Torrey, and only one WAYNE in Savage.  Of course, the absence of these families from New England would be irrelevant if the three married in England.  Richard LYON does appear to have married in England, to a woman whose name is unknown, though his second/last wife (named in his will) was Margaret __?__.  However, Richard is the eldest of the three, not the youngest, the only one who appears to have married in England, and the only one whose birth and death dates are close to being correct in this pedigree.
• Richard died in 1678, not 1676; and while his birthdate is unknown, 1609 is not unreasonable.  Dates for Henry and Thomas, however, are too early.  Henry's tombstone gives a birthdate of 1623/4, not 1603, and a deathdate of 1707/8, not 1671.  Thomas was born in 1621, not 1606, and he died in 1690, not 1660.
• We have no evidence for when these three LYONs (Henry, Richard, or Thomas) came to America, nor whether they came together.  They are not on any ship's passenger lists.  All we know is when they first show up in the records of New England — and they show up first in Connecticut, not New Jersey.  Only Henry went to New Jersey, and he did not go there until 1667.  Thomas was in Fairfield, CT, by 1647.  Henry shows up in Milford, CT, certainly by 1648, possibly as early as 1639.  Richard was in Fairfield by 1649.
• Need I go on...?
• UPDATE (15 Jun 2001).  Apparently I do need to go on.  For further discussion, please see this page.