In attempting to substantiate any idea of John Turk as father to James, and assure that path remains unsubstantiated, I contacted John A. I. McCurdy, author of books regarding the McCurdys of Northern Ireland, and a frequent contributor to Genforum and Rootsweb McCurdy research efforts.  I give first his kind and thorough response, and secondly my letter with its known data and queries:
 

Subj:  Re: Do you know anything of John Turk McCurdy and James his son?
Date:  15, September 2000 5.45.38 PM
From:  JAI.McCurdy@articlave68.freeserve.co.uk
To:    Alfonsa@aol.com
cc:  McCURDY-L@rootsweb.com, maccurdy@firedance.com

Dear Cynthia.
Re your query about John McCurdy nicknamed 'John Turk' I'm sorry but I have really nothing to contribute.I have seen mention of John Turk in several books including the Salisburys of c1893 (perhaps the earliest) and others. The tale seems to be that John Turk was one of the five McCurdy brothers who crossed to here in 1666 from Buteshire. Several other writers have used this story but I have yet to see any attempt to define the source record and its authenticity. Some writers say that John Turk crossed the Atlantic very shortly following his arrival in NI.  Others simply write him off with 'no further record' - I would like to know how they knew about his existence! Writers suggest that Patrick and his brothers were the founders of NI McCurdys but this is not so as there were some 35  McCurdy families here before 1666.I have not seen a copy of  'Larimers, McMasters andAllied Families' book by Mellon, Rachael Hughey Larimer, 1903. to which you refer.
Also the will of James McCurdy 1690-1771 is of great interest perhaps when you have something more on this from Jane Hodgson you might copy it to me?
Place names, if mentioned, would be very important.  Of course if John Turk was indeed the father of this James it would be very unlikely that John Turk went to America in the late 1660 or 1670s. I have found no record of any McCurdy being present at the Siege of Londonderry in 1689 either within or without the walls.
The will and the other matters (some of which are familiar to me) you mention seem to give you a well defined authentic line back to James.
'Turk' as a nickname could convey a picture of a rather adventurous headstrong young fellow, who paid scant attention to the advice of his
elders! (Fits many young men!)
Cynthia, it has been a pleasure to read your interesting letter - Thank you for sending it. I regret that I have been unable to provide information about John 'Turk'. Good Seeking!
Sincerely, John A I McCurdy
 

LETTER TO JOHN MCCURDY TO WHICH HE ANSWERED, ABOVE

Subj:  John Turk and James McCurdy
Date:  10, September 2000 10.52.41 AM
From:
To:    JAI.McCurdy@articlave68.freeserve.co.uk

To: Mr. John A I McCurdy
JAI.McCurdy@articlave68.freeserve.co.uk
(John has written about the McCurdys of Toberkeigh).
Sept 10, 2000

Dear Mr. McCurdy,
My name is Cynthia Swope, and my great grandmother, Nancy Moore McCurdy (B 1818 in Gettysburg, Adams Co., Penna and Died Aug 6, 1904 same place)  married John Adam Swope c. 1845. Since 1781, my direct  McCurdy line has resided  in Adams County, Penna.
It was suggested I reach out to you in efforts to pursue substantiation of my lineage via John Turk McCurdy and his son James (b 1690 and came to America about 1720-more below). I am new to this entire process and if I give information extraneous to  my query to you, PLEASE forgive me.

I have, at the core of my effort, only a collection of notes taken by my father who himself dabbled in genealogy in the precious little spare time he had, doing most of his work in the 1950s.  For the earlier McCurdys, the portion of the line about whom I am writing to you in hopes you can assist me, my father ...cited a book:The Larimers, McMasters and Allied Families, which was published in 1903 and was by R. H. Mellon. Beyond that I have recently been given information via The Ancestral McCurdys by H. Percy Blanchard (The Covenant Publishing Co., London, 1930), and an entry regarding James' will and testament (about which more may be found below) written by a descendant.

My father was very clear in his notes that I descend
from John Turk McCurdy ->James McCurdy (b 1690)->Robert McCurdy (B 1736 Salisbury township,  Lancaster co, Penna d. Adams co., Penna) m. Ann Creighton->etc.
Ultimately, I am seeking both  substantiation for and existence of  John Turk McCurdy and his son James (b 1690).  According to the Larimers, McMasters and Allied Families book by Mellon I mentioned above, (and this info is not sourced that I know of, but I do not have a copy of the book), "About the year 1666 the five McCurdy brothers (Patrick, David, William, John, and Daniel) sailed from Bute, Scotland, in an open boat to the north of Ireland; Patrick settled in the Cairn, Ballintoy, Antrim County, the others settled in Londonderry County.  After the siege John came to America.  It is surmised that "John Turk" was the father of James."
Title: The Larimer, McMasters and allied families
Authors: Mellon, Rachel Hughey Larimer , b. 1847 (Main Author).

However, attempting substantiation for John Turk McCurdy as one of the brothers and in response to a query I posted in the Bute, Scotland Rootsweb Forum,  I recently received reply sourced by a kind respondent indicating John's progeny are unknown. Again, the source this respondant sited is "The Ancestral McCurdys" by H. Percy Blanchard. The Covenant Publishing Co., London, 1930,pp. vii, ix, x, 30-33, 40.
 (pp. 30-31)
on a bitterly cold day in the latter part of November 1666. Patrick, David, William, John,and Daniel sailed "to the Island of Rathlin, and the next day to the mainland of Ireland near Ballintoy."
On page 40, Blanchard  states:
John McCurdy, "the Refugee," the fourth of the brothers, was born about 1646. He moved as a young man to America.There is no further trace of him or of any possible descendants. There is nothing definitely to indicate or point to the likelihood that he left any posterity".

Now I have something else about this James and his father John Turk.
This was   recently emailed me by  Jane Hodgson, who  is involved with me in my effort being herself interested in this line.  This link seems more promising, as it has attached the copy of  a will that apparantly I may, with some work, be able to access, and apparantly was in a booklet, with a copy of a will attached.  What the booklet is exactly I am not sure  and have to ask Jane. However, here is the info pertinent.
James McCurdy, No. 1
1690-1771
"My great-great-great-grandfather, James McCurdy, emigrated to America about the year 1720.  His father, probably the one known as "John Turk," took part in the siege of Londonderry as the besieged, 1689.  They owned a property in Antrim County, about two miles from the "Giants' Causeway," known as Bushmills. James after marrying a Scotch lass named Cooke, sailed for Pennsylvania. After a voyage of six months the captain found himself in the mouth of the James River in Virginia.  The vessel was put about, and in due time arrived at the head-waters of the Elk River, in Maryland.  Their first child was born in Maryland about 1720.  They removed to Lancaster County, Pennsylvania, where James McCurdy bought some hundreds of acres of land in Salisbury township, near the old Pequea Church, where George Whitfield preached.  For this land he obtained a general warrantee.  One tract of land of which we have an account was of two hundred acres, date of survey February fourteenth, 1738, Lancaster County.  The Episcopal Church attempted to take this land for "glebe" purposes, and a suit was the result, which lasted for seven years in the courts then held in Philadelphia, resulting finally in establishing the McCurdy claim.  He died in 1771, leaving four sons."

A copy of a will is attached:
Salisbury Township, Lancaster County, PA
Son Archibald
Son Robert
Son Hugh
Son James

5 Mar 1770
Witnesses Robert Armor, Robert McNeil, James Clemson

The four sons of this will include Robert (b 1736) married Creighton, who is my gggg grandfather.

I am confident in my lineage back to Robert and, because of this will,  that he had a father James McCurdy.  But James himself, and his own father , well I'm befuddled.
Please sir, Do you know anything of John Turk McCurdy and James his son?
In addition, could you clarify what the "Turk" might mean?
I thank you in advance for reading this lengthy correspondence, and most gratefully for any reply you give to it.

Sincerely,
Cynthia Swope
NY NY