* There are no surviving subsequent company muster rolls which does not permit us to ascertain his later service
M323: Compiled Service Records of Confederate Soldiers Who Served in Organizations from the State of Texas
They served in the Atlanta Campaign July 20 - Sept. 2, 1864.
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EIGHTEENTH TEXAS CAVALRY. The Eighteenth Texas Cavalry, also known as Darnell's Cavalry Regiment, was organized at Dallas, Texas, on March 15, 1862. The regiment initially had ten companies lettered A to K comprising men from the counties of Bastrop, Bell, Dallas, Denton, Ellis, Harris, Henderson, Johnson, Travis, and Williamson. Commanding the regiment was Col. Nicholas H. Darnell with field officers Lt. Col. John T. Coit, Maj. Charles C. Morgan, and Maj. William A. Ryan. The regiment was first assigned to duty in the Indian Territory where it became involved in a dispute with that area's commanding officer Gen. Albert Pike. The dispute stemmed from the regiment moving its camp without notifying General Pike. Soon after, the regiment was dismounted in April 1862 and transferred to Arkansas Post, Arkansas, in August 1862. The regiment fought in the battle of Arkansas Post that started on January 4, 1863, and was captured by Union forces at the conclusion of fighting on January 11.
http://www.tshaonline.org/handbook/online/articles/qke04
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Report of Capt. William H. Perry, Eighteenth Texas Cavalry, commanding
Seventeenth and Eighteenth Texas Cavalry (dismounted),
of operations July 20-22.
ATLANTA, August 2, 1864.
Report of the Seventeenth and Eighteenth Texas Cavalry in the
engagement of the 20th, 21st, and 22d of July before Atlanta.
July 20, we did not participate in the engagement, being in reserve
for Gen. Cheatham's division. We were exposed to some
extent to the shells of the enemy. Loss of the regiment 2 men
wounded. 21st, at daylight we formed our line within 250 or 300
yards of the enemy's pickets, and some 500 or 600 yards from the
main line of the enemy's works, they having previously built works.
We at once began throwing up works under a heavy fire from the pickets
of the enemy. The regiment sustained some loss while building
our works. About 9 a. m. the enemy advanced with two or three lines
of battle, driving our pickets and rushing on to get possession of our
line. They were met with a volley of bullets and turned their
course. After rallying and making several faint charges they disappeared.
The loss of the enemy was heavy. The regiment did
not suffer but little from the minie-balls, but suffered heavily from
shells, the enemy having an enfilading fire upon our lines.
The regiment had 184 rank and file. Loss during the day-killed,
1 captain, l lieutenant, and 10 non-commissioned officers and privates;
wounded, 3 lieutenants, 36 non-commissioned officers and privates.
I suppose the enemy must have had 6,000 or 8,000 in the
engagement. No captures were made.
July 22; the regiment went into the action with about 160 men.
The cook detail having been ordered in, and the picket that had been
left on the line some two or three days previously having come up,
we advanced rapidly upon the enemy and in good order, notwithstanding
the thick undergrowth and the marshy ravines we had to
pass through. We drove the enemy about a mile, taking two lines
of works. We then emerged into an open field and advanced to the
third line on double-quick, the enemy pouring musketry into us from
our front and right flank, playing on us at the same time with cannon.
The right of the brigade, having engaged the enemy, failed
to move forward with us and left our flank exposed. Not until we
had reached the third line did we discover that we had no support
on our right with the exception of the left wing of the Fifth Confederate
Regt. We were separated from the left of the brigade
by a marshy ravine and an angle in the works. The brigade received
orders to move out by the left flank as soon as our position
was ascertained, but the orders failed to reach our regiment. Captain
Manion; commanding the regiment at that time; sent Lieutenants
McKnight and Little to Gen. Smith for orders and to know
what to do; but before they could return the enemy made several
charges upon us and had succeeded in getting in our rear. We fought
the overwhelming forces of the enemy in almost a hand-to-hand encounter
until further resistance would have been folly. Thus it was
that many of our gallant men fell into the hands of the enemy. I
know nothing of the killed and wounded after the occupation of the
third line. We captured several pieces of artillery, wagons, ambulances,
horses, and several hundred stand of small-arms. I saw
some five or six pieces of artillery, several wagons and ambulances
our regiment ran over; also many horses and mules. As soon as it
was ascertained that Maj. Person (senior officer) had surrendered
us, many made their escape by running. We made a second charge
upon the enemy's works late in the evening, but did not succeed in
taking the works, the brigade on our right not coming up and the
enemy having an enfilading fire upon us. Many of our regiment
went to the works on the left, it being put on the left of the brigade
late in the evening.
Loss, so far as I can ascertain, was-killed, 1 captain, 3 non-commissioned
officers and privates; wounded, 2 officers, 4 non-commissioned
officers and privates. Many others may have fallen victims
to the enemy's missiles, but we not being able to hold the ground we
took, I could not learn anything of the number.
W. H. PERRY,
Capt., Cmdg. Regt.
Source: Official Records
CHAP. L.] REPORTS, ETC.--CONFEDERATE. PAGE 751-74
[Series I. Vol. 38. Part III, Reports. Serial No. 74.]