1.  Illinois Statewide Marriage Index, 1763–1900:

Sias, Archelaus Jr

Turner, Martha Jane (d/o Cyrus)

06/07/1848

Book A, p. 14

Lic#577

McHenry

2a.  1850 Census Index/Microfilm (online at Genealogy.com, Image #1 of 8 — mis-enumerated as being on the "Consumnes" and mis-indexed as being on the "Consumers" River):  Cosumnes River, Sacramento Co., CA, Roll 35 (Book 1), p. 242A, 3/3 (this census-taker restarted the household/family numbers with each new page), enumerated 17 Sep 1850 (extracted by Diana Gale Matthiesen):¤

Archelaus Sias	34	M	Miner, for gold		Vt
Augustus C. Turner	22	m	"       "		NY
[six other miners, none of whom were from VT]

Is this our subject?  And is Augustus a brother of Martha?  Obviously, Martha Jane is not with him, but most of the many married men who came to the gold fields did not bring their families with them.  (There is no "Consumers" or "Consumnes" River in California; it's the "Cosumnes River," which river flows from the foothills of the Sierra Nevada — the undoubted location of the gold camps — westward from El Dorado Co. into Sacramento Co., where it merges into the Sacramento/San Joaquin River Delta.)

2b.  1850 Census Index/Images (online at Ancestry.com; Image #4 of 22):  Town of Greenwood, McHenry Co., IL, p. 4170B, 23/23, enumerated 4 Nov 1860, official enumeration date 1 Jun 1850 (extracted by Diana Gale Matthiesen):

Cyrus Turner	63	M		Farmer	1320	RI
Catharine "	57	F				NY
Catharine Hopkins	11	F				"

Martha Jane is obviously not living with her parents.  I did a page-by-page search of Greenwood and did not find her, but I did find the next record using the indices…

2c.  1850 Census Index/Images (online at Ancestry.com; Image #6 of 29 — indexed "Syvens"):  Town of McHenry, McHenry Co., IL, Roll 117 (Book 1), p. 492B, 47/47, enumerated 11 Nov 1850, official enumeration date 1 Jun 1850 (extracted by Diana Gale Matthiesen):

A H Nixon	25	M		Merchant	800	Vermont
Artemus "	?0	M		"		Mass
Betesy    "	60	F				N H
Sophia C N "	37	F				"
Mary C Prority?	35	F				Vt
Caroline M Nixon	32	F				"
Jane Syrers	19	F				NY
Olivia B Norton	17	F				Vt
Mary C Peroty?	16	F				"

3.  1860 Census Index/Images (online at Genealogy.com, Image #5 of 8 — indexed "Lias"):  Antelope P.O., Spring Valley Twp., Colusa Co., CA, Roll 57 (Book 1), p. 433, PN 15, 162/132, enumerated 13 Jun 1860, official enumeration date 1 Jun 1860 (extracted by Diana Gale Matthiesen):

A Lias	45	M		Common School Teacher	700	1000	Vermont
Martha J Lias	30	F					New York
Phebe H Lias	8	F					Illinois
Florence Lias	5	M					Do

It really is "Lias."

4.  1870 Census Index/Images (online at Genealogy.com, Image #5 of 48 — indexed "Architus"):  Woodland P.O., Grafton Twp., Yolo Co., CA, Roll 93 (Book 1), p. 480A, PN 5, 55/54, enumerated 27 Jul 1870, official enumeration date 1 Jun 1870 (extracted by Diana Gale Matthiesen):¤

Sias Archilus	54	M	W	Merchant	1500	2000	Vermont
____ Martha J	39	F	W	Keeping House			New York
____ Phoeba H	18	F	W				Illinois
____ Florence	15	F	W				Illinois
Hunstor Robert	28	M	W	Merchant			New York

5.  Messages posted to the McHenry County, Illinois board (online at Ancestry.com).