The other monument at Fort Donelson is for the two Texas regiments who fought here, even though one of them fought here a year later.
The 7th Texas Infantry was part of the force that cleared an escape route for the Confederates before the high command gave up the effort and doomed the garrison to capture. A year later, 3 February 1863, the 8th Texas Cavalry fought here as part of General Wheeler's attack on Dover. That attack failed but the 8th Texas performed its job well, keeping Union reinforcements away from Wheeler's force.
This monument is similar to other Texas monuments in that it was placed during the centennial celebrations, this one actually was placed in 1964, not sure why they didn't hit the 1862 or 1863 anniversaries.