The 1st New York Artillery, Battery G served as a member of Fitzhugh’s Brigade in the Artillery Reserve, Army of the Potomac. Battery G, First New York Light Artillery was recruited at Mexico, Oswego County, New York, by Marshall H. Rundell and Nelson Ames, in September, 1861. It joined the regiment at the general rendezvous at Elmira, and was there mustered into the United States service for three years, September 24, 1861, by Captain Tidball, United States army mustering officer, with the following officers: Capt. J. D. Frank, First Lieut. Nelson Ames, Second Lieut. Marshall H. Rundell. The battery was engaged with the enemy in every battle the Second Army Corps participated in during the war, as shown by the company records. They had 11 officers and men killed, 31 men wounded, and 15 died of disease, a total loss of 57 officers and men. Capt. Nelson Ames and Lieut. S. A. Mc-Clellan were also wounded during the terms of their service. Battery G was never driven by the enemy's fire from a position it was ordered to hold, never fell back until ordered, and never lost a gun or carriage of any kind during its term of service.
This battery was commanded by Capt. Nelson Ames (1836-1907), a native of Mexico, New York. He was wounded during the Overland Campaign of 1864 and was the post-war mayor of Marshalltown, Iowa. For Gettysburg, Ames reported, "During the night of the 2d we refilled our ammunition chests and refitted the battery ready for action. July 3d we were in position with the Second Corps on the front line of battle, and took part in the terrible artillery duel, also in repelling Pickett's charge, and thus ending one of the most fearful battles of the war." Ames also wrote a book, published in 1900 entitled, History of Battery G, First regiment, New York light artillery. Ames' obituary found in the New York Times, published March 9, 1907 can be found HERE.
The Battery G, 1st New York Artillery July 3 Position Marker is located at the southern part of 
Hancock Avenue (RD310), just past the intersection where Sedgwick Road changes its name to Hancock. United States Avenue also runs perpendicular at this intersection, 237 feet to the south. This position marker is accompanied by two altered six-pound bronze cannons. All of this is located on the left or west side of the road if traveling north along the avenue. It seems most of the monuments here have artillery pieces on both flanks like this monument. There is a long string of these set up on both sides of the road kind of terminating at the Pennsylvania Monument (MN260); this is the first in that long line along Hancock Avenue. The cannons face due west, in the direction where the Union position was defending on July 3, 1863. This area is an absolute beehive of activity as this site represents the best of what Gettysburg has to offer, both historically and monumentally. Parking is plentiful and is available road-side at intermittently enlarged shoulder cut-outs, usually marked with white striping. Be sure to keep vehicles off the grass or you will be ticketed by park police. I visited the monument on Thursday, July 5, 2012 @ 5:34 PM, EDT & @ an altitude of 566 feet, ASL. I used a Canon PowerShot 14.1 Megapixel, SX210 IS digital camera for the photos.
Often, state regiment monuments are also accompanied by secondary monument which designate positions maintained from July 1-3, 1863 as well as flank monuments to delineate the ends of troop lines. The primary Battery G, 1st New York Artillery Monument (MN178-E) only has this one position marker and no flank markers. This Third Day marker lies 0.84 miles westish (262°) from the primary monument located in the Peach Orchard. The position monuments was dedicated on May 20, 1889 by the State of New York whereas the primary monument was dedicated on July 3, 1893, almost a full four years after the secondary monument, for some reason. This markers is composed of granite with a slanted front upon which rest the incised inscription. The monument is very, roughly hewn save the slanted face which is smooth & polished. The marker is 1'x1'6"x2'8". Additional details from the nomination form concerning the flank monuments may be found below in red. The inscription reads:
Battery G
(Ames)
1st N.Y.L.A.
July 3rd 1863.
The Battery G, 1st New York Artillery Monument & position marker are contributing features to the Gettysburg National Military Park Historic District which is nationally significant under NR Criteria A, B, C & D. Areas of Significance: Military, Politics/Government, Landscape Architecture, Conservation, Archeology-Historic. Period of Significance: 1863-1938. The original National Register Nomination was approved by the Keeper March 19, 1975. An update to this nomination was approved by the Keeper on January 23, 2004. Collectively, the monuments are identified as structures number MN178-E.
From the Nomination Form:
1 of 90 mns in Park to NY commands in Gettysburg Campaign. Mark position held by battery during July 2, 1863 when supporting the III Corps slaient there. Located in Peach Orchard facing Emmitsburg Rd; Position marker at line held on July 3, at Hancock Ave, near United States Ave.
Short Physical Description:
Mn w/ 2 bronze cannons & position marker w/ 2 altered 6-lb bronze cannons. Rough-hewn base 6'4" sq. Granite shaft w/apex cap w/ cornice & polished sphere; insciptions, relief, 2'1"x1'6" & bronze state seal on W. Bronze inscription tablet 2'6"x1'6" on E. All 18'4"H. Marker 1'x1'6"x2'8",slant-face.
Long Physical Description:
Monument that has two bronze Napoleon cannons and a position marker with two altered six-pound bronze cannon. Monument is a granite shaft with an apex cap that has a cornice and polished sphere and set on a 6.4 foot square rough hewn base. The shaft contains inscriptions, a relief, and a bronze state seal on the west side and a bronze inscription tablet on the east face. Overall height is 18.4 foot. The position marker has a slant face, 1x1.6 foot. Monument is located in the Peach Orchard facing Emmitsburg Road. Position marker is on Hancock Avenue, near United States Avenue. [Much smaller granite marker secondary to this - MT]
My Sources
1. NRHP Narrative
2. Stone Sentinels
3. Virtual Gettysburg
4. Draw the Sword
5. Historical Marker Database