This Battery was part of Alexander’s Battalion which served as a member of the Artillery Reserve in the First Corps, Army of Northern Virginia. The Battalion commander, Colonel Edward Porter Alexander (1827-1911) (May 26, 1835 – April 28, 1910), was an engineer, an officer in the U.S. Army, a Confederate general in the American Civil War, and later a railroad executive, planter, and author. This battery (the subject of this waymark) however, was commanded by Lieut. S. Capers Gilbert
The Rhett's Brooks Artillery - CS Battery Marker and cannons are southwest of Gettysburg, on the left or east side of West Confederate Avenue if traveling south and 260 feet before the Millerstown Road Intersection. The Mississippi State Monument is directly to the rear or east of the monument. 
Cars are also allowed to park on the side of the road at intermittent cutouts; there is a cutout located here. When visiting this and other monumentation and tablets, avoid parking on anything green or you will be ticketed by the park police. They almost got me. I visited this monument on Saturday, March 10, 2012 at approximately 3:31 PM, just before the clocks were set ahead for the Spring. I was at 609 feet ASL elevation.
These monuments were first built in 1900 and concluded in 1906 according to the NRHP nomination form. Some sites have the monuments being erected in 1910 or later; the NRHP also has this specific one at 1893 ending in 1900 so it would seem the current NPS is clueless about the installation date. 1910 seems to be the most reasonable date so we will go with that. It is amazing with all the work and effort exerted to make the Gettysburg National Military Park a reality, no one took the time to keep accurate records and correct installation dates. The work was done under the direction of the Gettysburg National Park Commission (established by the United States Department of War), after they took over the administration of the park from the Gettysburg Battlefield Memorial Association (whose funds had expired) on March 3, 1893, and whose stewardship was then transferred to the National Park Service in 1933 SOURCE.
Draw the Sword, with descriptive help from the NPS site, offers the following description: Cast iron tablet, 3’8" x 3’4", with raised inscription painted in a contrasting color and mounted on fluted cast iron post. All 4’4" H. Tablets casts by Calvin Gilbert. The inscription on the 3.8' x 3.4' tablet narrates the events associated with Battery during the Battle. The inscription on the monument reads:
Army of Northern Virginia
Longstreet's Corps Artillery Reserve
Alexander's Battalion Rhett's Battery
The Brooks Artillery
Four 12 Pounder Howitzers
July 2 Took position here at 4 p.m. and opened fire. When the charge was made on the Peach Orchard moved to a point near there and with other batteries supported the infantry in its further advance. Assisted in harassing the retiring Union forces causing them to abandon temporarily several guns. Continued firing until night and aided in preventing pursuit of the Confederate advanced lines when they fell back shortly before dark
July 3 In position at dawn in the artillery line on the ridge running north from the Peach Orchard and on duty there all day. Took part in the cannonade preceding Longstreet's assault and retired from the front after night
July 4 Remained near here until 4 p.m. and then withdrew to Marsh Creek on the Fairfield Road
Losses heavy but not reported in detail
There are scores of similar monuments for the various Confederate States & Union units which fought at Gettysburg. Four designs represent brigade, division, corps and army headquarters, and each has elements which identify it as Union or Confederate. Many of the tablets were created by Albert Russell & Sons Co. of Newburyport, Massachusetts and are made of granite, bronze and concrete or like this one, cast iron. All of these tablets were designed by architect Colonel Emmor Bradley Cope (July 23, 1834 - May 28, 1927). He designed pretty much every tablet for both the Union and Confederate armies, each one distinct, with several different varieties. He is buried in Evergreen Cemetery in Gettysburg, as well as he should be as this park and most of the things seen here today were designed by him and as such, are his legacy. These monuments/tablets were erected just after the turn of the century during the first and beginning of the second decade of the 20th century. Each one has since been preserved or restored at least twice since the turn of the 21st century. The plaques and tablets were erected by the Gettysburg Park Commission (established by the War Department). The Gettysburg Park Commission is also referred to as the Gettysburg National Military Park Commission or the Gettysburg National Park Commission, to clear up any confusions, especially my own.
On October 1, 1898, the Gettysburg National Park Commission in a letter to the Secretary of War set gave recommendations for continuing the task of organizing and progressing the work of the Gettysburg National Military Park. Every November they wrote their annual report which outlined the work of the GNPC for that year. The following is an excerpt from that report relevant to this waymark. The link at the end of the paragraph will take you to the entire report. The method of marking the positions of troops on this field, as approved by the War Department, is to place the principal tablet or monument of each command at the position occupied by the command in the main line of battle, and to mark the several important positions subsequently reached by each command in the course of the battle by subordinate and ancillary tablets, with appropriate brief inscriptions giving interesting details and occurrences and noting the day and hour as nearly as possible. SOURCE
Most of the Commission reports have been digitized and can be found HERE. The initial 1893 report up to and including 1921 can be found here. 1922 to 1926 are missing and have yet to be discovered. The years 1927 to 1933 were discovered in 1996 and are also included. To my knowledge this is the most comprehensive list of documents that illustrated the development and formation of the park.
Information about these specific types of monuments:
CONFEDERATE BATTERY AND BRIGADE TABLETS (ADVANCED POSITION)
These tablets are 3’8" x 3’4" in dimensions, with carefully prepared inscriptions cast in raised letters painted in white (contrasting the black background) describing the part taken in the battle by each brigade, their position and stating its numbers and losses so far as practicable to obtain. They are mounted on iron pillars or fluted cast iron posts about 3 feet high, grouted in the ground, and the tablets are inclined at a suitable angle so that the inscriptions can easily be read by persons riding or driving on the avenue. Every tablet is 4’4" in height. The advance position markers were cast by Calvin Gilbert. SOURCE & SOURCE
The Rhett's Brooks Artillery - CS Battery Marker is a contributing feature 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. The monument is identified as structure number MN568-B.
From the Nomination Form:
Civil War tablet that marks position of Rhett's CS Battery during July 2-4, 1863. Narrates events associated w/ Battery during Battle.
Short Physical Description:
Cast iron tablet, 3'8" x 3'4", with raised inscription painted in a contrasting color and mounted on fluted cast iron post. All 4'4" H.
Long Physical Description:
Located on E side of West Confederate Avenue, north of Millerstown Road.
My Sources
1.
NRHP Nomination Form
2.
Stone Sentinels
3.
Virtual Gettysburg
4.
Draw the Sword
5.
Historical Marker Database
6.
Find a Grave Memorial