I came across this system in some info I got from the FCHS and cannot figure out who is related to whom, if anyone at all. Can anyone explain this to me, please?
here's some info from a book called Genealogical Index to Frederick County, Maryland, The First Hundred Years by John Stanwood Martin, Vol. III, L-R. At this point I am not sure exactly what some of it means by here goes:

"*MARK ** Generation # ******
(vs Marks, Marx) ( ) HFCM/NIS: Mark-7, Marke-1, Marks-2, Marx-1
* MARK ** Generation # 57 (B.1695-1724) ******
Robert 20155 ( )
(Marks) Patented "Shettle" 1743 (POOMp245) Shoemaker who left Co.
by 1753 owing money (M&Cv1p108)
Robert 34282 ( ) m. Scharlott, Cath. 34283-34284 (7 Nov. 1743 - my note)
(MDRECv1-All Sts. -p260)
Ch: Margaret 34285, Thomas 34286, Robert 34287
* MARK ** Generation # 58 (b. 1725-1754) ******
Frederick 33809 ( ) (Marks) (MDRECv1p287-1796)
James 56816 ( ) (Mark) (Jr) Sig.pet.1766 (M&Cv1p95)
John 33737 ( ) (Marks) (MDRECv1p.286-1796)
Margaret 34285-34282 (Robert) b1744 (MDRECv1-All Sts. - p.260)
Peter 54679 ( ) m.-Anna Maria; (Marks) Ch.bp.1785 (RERCFp54)
Ch: Michael 54680
Robert 34287-34282 (Robert) b. 1751 (MDRECv1-All Sts.-p260)
Thomas 34286-34282 (Robert) m.-,Eliz.b.1747 (MDRECv1-All Sts.-p.260) Wit. 1785 Ch.bp.1790 (RERCFp65, 93)
Ch: Eliz. 55195
William 33252 ( ) (Markes) (MDRECv1p.278-1796)
* MARK ** Generation # 59 (b. 1755-1784) ******
.... 10752 ( ) m. Clabaugh, Cath. 46987-46985; (WMGv5p167)
Anna Maria 45185 ( ) m.Protzman/John Jacob, Protzman 45177-15166
(Marks) Her father, with whom her family lived, objected to
baptizing the children so it was long withheld. (MFGMp75
Eliz. 12030 ( ) m. Warner/Werner, Jacob, 1787 14260
(Marx) (MM1778-Zion.Luth)
Eliz. 55195-34286 (Thomas) b. 1790 (RERCFp65)
George 17277 ( ) m. Purdy, Cynthia, 1807 17278 (MLFC)
James 01641 ( ) Fred.Co.off.1803 (HFCMp603) (HWMp482c2)
Margaret 08798 ( ) m. Baker, Larkin 1799 08797; (MM1778)
Michael 54680-54679 (Peter) (Marks) b.1785 (RERCFp54)
Milly 16996 ( ) m.Kent, Isaac, 1801 16995; (Marks) (MLFC)
Peggy 17522 ( ) m. Murphy, John 1802 17521; (Marks) (MLFC)
* MARK ** Generation # 60 (b. 1785-1814) ******
Eleanor 21580 ( ) m. Baker, Robert, 1811 21579; (Marke) (MLFC1811)
Eliz 34518 ( ) m. Shaner, Melcher, 1819 34517; (Marks) (MLFC1811)
Eliz. 27367 ( ) m. Hilleary, Howard, 1840 27366; (MLFC1811)
Eliz. 30497 ( ) m.Moberly/Mobly/Mobbly, Thomas, 1812 30496
(MLFC1811)
Emeline 36323 ( ) m. Thompson, Smallwood M., 1828 36322; (MLFC1811)
Henry 29645 ( ) m.Boyer, Susanna, 1818 29646 (MLFC1811)
Jacob 57270 ( ) (Marx) c 1809-18 (NIS-Emtsb.Luth)
Lemuel 56627 ( ) m. - Susan A. 1824-91; 1814-85 (NIS-Frdk.Mt.01)
Nimrod 29647 ( ) m. Haislup, Isabella, 1836 29648; (MLFC1811)
Rachel Ann 30315 ( ) m. Miles, John Thomas, 1835 30314; (Marke) (MLFC1811)
Sarah 24250 ( ) m. Day, James 1823 24249; (MLFC1811)
Ury 35487 ( ) m. Spencer, Wm., 1814 35486; (Marks) (MLFC1811)
Zeruia 37382 ( ) m. Whitter, Isaac, 1834 37381; (MLFC1811)

I cannot tell nor can I remember how the people in generations are numbered so I cannot tell for sure who is related to who. It looks like there may have been several Mark/Marks/Marx families in Frederick County. Do you