1.  Marriage Record:

2.  1880 Census Every-Name-Index/Images (online at Ancestry.com):  there is a  Charles CUMMINGS (æ 22, b. NY, unmarried) living with his parents, Walter CUMMINGS (æ 48, b. NY, wife Jane), in Clayton, Jefferson Co., NY (p. 269A), who is probably our subject.  The Charles W. CUMMINGS (1857-1924) of Delaware Co., NY, is already married and living with his wife in Delaware Co., NY.

3.  1890 Census:  the 1890 Census Population Schedules were destroyed.

4.  1900 Census Index/Images (online at Genealogy.com, Image #75 of 95):  Clayton Village, Clayton Town, Jefferson Co., NY, Roll 1041 (Book 1), p. 243A, SN 10, SD 6, ED 16, enumerated 14 Jun 1900, official enumeration date 1 Jun 1900 (extracted by Diana Gale Matthiesen):

1900:  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	11	12	13	14	15	16	17	19	21	22	23	24	25	27
198	212	Cummings Charles W	Head	W	M	Nov 1858	41	M	13			NY	NY	NY					Y	Y	Y	R	H
		________ Mary C	Wife	W	F	Aug 1867	32	M	13	2	2	Can Eng	Ire	Ire	1889	17			Y	Y	Y
		________ Jennie Mary?	Dau	W	F	May 1888	12	S				NY	NY	Can Eng			At School	8	Y	Y	Y
		________ Walter P	Son	W	M	Mar 1890	10	S				Can Eng	NY	Can Eng			At School	8	Y	Y	Y

I initially thought this might be the 1900 census record of the Charles W. CUMMINGS (1857-1924) who otherwise lived in Delaware Co., NY (and whom I cannot find in the 1900 census), but despite some amazing similarities, they are apparently different persons.

5.  1910 Census Images (online at Ancestry.com):  can't find.