The next year, 1837, Mercer, now in West Virginia but adjoining Giles County, Virginia, was formed. The Act authorizing its creation is as follows: "All that part of the counties of Giles and Tazewell contained within the following boundary lines ... shall form one distinct and new county and be called and known by the name of Mercer county in memory of general Hugh Mercer who fell at Princeton." Appropriately the county seat of Mercer County is Princeton. In 1838 the Virginia counties of Greene and Roanoke were set up. The Act for the former county is as follows: "So much of the county of Orange as it lies next to and adjoining the counties of Madison, Rockingham and Albemarle and west of a line beginning at Cave's old mill (now James Jackson's) on the Madison county line and running thence a straight line to where Whitelow's mill run intersects the Albemarle county line shall form one distinct and new county and be called and known by the name of Greene county in memory of general Nathaniel Greene who served his country in the revolutionary war." It may be mentioned that this is the second county in Virginia honoring General Greene. The correct spelling for his first name is Nathanael. In Greene County lies Swift Run Gap. This is the gap in the Blue Ridge mountains over which in September 1715, Governor Spotswood led his adventurous band into the beautiful Valley of Virginia. Westward expansion began at this date. The second county created in 1838 was Roanoke composed of that portion of Botetourt lying next to the southwestern parts of Montgomery, Franklin and Bedford. Roanoke was the name applied by the early colonists to the shell-beads of different colors used by the Indians as a medium of exchange. The river had long been known as Roanoke, hence it seems likely that the county took its name from the river. Roanoke County is thus bounded: "beginning at a point on the Blue ridge which divides the counties of Bedford and Botetourt, thence northwest to the house now the residence of John Bonsack on Glade creek so as to include the said Bonsack in the new county, thence a line to the house of Thomas Barnes including said Barnes in the county, and so as to leave John W. Thompson in the county of Botetourt, thence a straight line crossing the Catawba Valley at a point one mile due north of Mrs. Garwood's; thence crossing Craig's creek (passing the house of John Spessard on Craig's creek so as to leave the said Spessard in the old county) to the top of the mountain which divides the waters of Craig's creek and Sinking creek, thence westwardly along the top of the mountain to the point where the lines of Botetourt, Montgomery and Giles counties meet, thence with the line which divided the county of Botetourt from the county of Montgomery to the point at which the said line joins the Bedford line, thence with the Bedford line to the beginning."