1.  Missouri Marriage Records.  Missouri State Archives (microfilm), Jefferson City, MO (online at Ancestry.com):

Miliard W Cuff

Isabele W Pond

8 Jul 1877

Grundy County

2.  1860 Census Every-Name-Index/Images (online at Ancestry.com):--Millard CUPP (æ 4, b. KY) is living in Mason Co., KY, with his parents (q.v.).  Isabelle not found, so her age is probably correct in 1870, but incorrect in 1880.  Perhaps she later lied about her age, so she could get married without her parents' permission.

3.  1870 Census Every-Name-Index/Images (online at Ancestry.com):--Millard W. CUPP (æ 13, b. KY) is living in Grundy Co., MO, with his parents (q.v.).  Isabella POND (æ 9, b. MO) is living in Trenton Twp., Grundy Co., MO (p. 399B), with her parents, Warren POND (æ 60, b. IN) & Lucinda (æ 45, b. IN), plus siblings.  This record opens a can of worms I don't care to resolve.  Warren Sherman POND (1806-1891) is said to have married first to Lucinda McCLURE (1808-1839) on 2 Apr 1828 in Franklin Co., IN.  Warren is said to have married second on 3 May 1840 in Franklin Co., IN, to Emily FEWEL (1823-1885).  The hitch is that Warren's wife in the 1870 census is "Lucinda."  In the 1860 census, she is "Amelia," and in the 1880 census, she is "Emily." 

4.  1880 Census Every-Name-Index/Images (online at Ancestry.com, Image #1 of 12):  Jackson Twp., Grundy Co., MO, Roll T9_688 (Book 1), p. 463A, PN 1, SD 7, ED 218, enumerated 1/2 Jun 1880, official enumeration date 1 Jun 1880 (extracted by Diana Gale Matthiesen):¤•

1880:  for an explanation of the column headings, please see What the Numbers in the Federal Census Mean (missing columns contained no data).

1

2

3

4

5

6

7

8

9

10

13

24

25

26

11

12

Cupp M W

W

M

24

/

Farmer

KY

KY

KY

____ I W

W

F

21

Wife

/

Housekeeping

MO

KY

IN

____ O G

W

M

10/12

Mar

Son

/

MO

KY

MO

Ware M J

W

F

20

Visitor

/

MO

MO

KY

5.  1890 Census:  the 1890 Census Population Schedules were destroyed.

6.  1900 Census Every-Name-Index/Images (online at Ancestry.com):  can't find Isabelle.  If she's alive, she has probably remarried.  There are no CUPPs in Grundy Co., MO, except Millard's widowed mother and an unmarried sister.

7.  Tolle Cemetery, Jackson Township, Grundy County, MO (online at the Grundy County MOGenWeb site):

CUPP	Willard		02 Dec 1883	27y 7m 8d. h/o L. T. (POND)
CUPP	Angus		1882	11m. s/o Willard & L. T. (POND) CUPP.

It appears the stone has been mis-read because, in the censuses, he is clearly Millard, and she is clearly Isabelle W. POND.  The notes on these readings don't necessarily indicate the information was on the stone; some is added by the compilers, often erroneously, which is a good reason to always record data verbatim, without adding to it.