Fortification Friday: The Forts of St. Louis

Most postings this week have centered on the 2nd Missouri Artillery and St. Louis.  So I figured to continue that theme here on Friday and look at the fortifications, mentioned in earlier posts, were that regiment served at the end of June 1863.

St. Louis was an important city for the Federal war effort.  It’s shipyards turned out steamboats and ironclads to ply the western waterways.  Factories produced equipment and materials, to include cannon.  An arsenal and barracks complex provided staging points for men and materials.  The riverways, railroads, and road infrastructure made St. Louis an important logistical center.  And of course, it was famously the “Gateway to the West.”

Looking beyond just pure military matters, St. Louis was important politically for the control of Missouri.  As the state’s most populous corner, the side which controlled St. Louis had much more sway, politically, over the rest of the state (a problem “rural” Missourians complain about even to this day).   Had Missouri swung from “disputed border state” over to a “Confederate state” early in the war, the rebels could directly threaten the Old Northwest states and those of the upper Mississippi Valley.  Not to say the prospects for such a turn were likely.  Rather just to say St. Louis was more important than just a place for factories, shipyards, docks, and warehouses.  It was also the key to holding Missouri in the Union.

That said, St. Louis had to be defended.  That’s where the 2nd Missouri Artillery and other units factored in.  The city was defended by a series of forts first laid out in 1861 and not completed… well… by some measure never fully completed.  To understand the layout, we have to think of the city as it was in 1861, rolling back the sprawl that is today.  At that time, the city’s western outskirts were along Grand Avenue.  So, generally speaking, the engineers laid out a defensive line along Grand Avenue, which swept back on the north and south ends to meet the river.   The only wartime depiction of this arrangement comes from a set of engineer diagrams:


Note the north seeking arrow points to the right. The diagram is not to scale, but does show in … shall we say schematic… the arrangements.  Lacking, of course, is the run of Grand Avenue.  While useful, this diagram is far from idea.  Some good work was done by Chris Naffzinger recently, correlating the fort locations to points in an 1870 Pictorial Survey (Compton & Dry).  My intention, last night when drafting this post, was to build upon that by using an 1870 street map of St. Louis to “go between” the engineers diagram and the pictorial survey map.  But that task is a bit more complex than first assess… and will have to wait.

But what I would like to do is walk through the forts and arrangements, looking at the particular features seen.  There were ten numbered forts along with six detached batteries, which used letters for designations.

Fort No. 1: Anchoring the left of the line and situated along Chippewa Avenue.


Three bastions connected with curtains to form a neat triangle. Notice inside is a blockhouse, taking up most of the interior, with bunks for 190 men.  A traverse covers the entrance to the blockhouse.  And in that traverse is a powder magazine.  About 400 feet on each face. While the shape is not what we come to expect for a bastion fort, it complies with Mahan’s instructions.  One departure of note, if you look at the profile A-B given in the upper left.  The bastion had an open gallery covered by a stockade.  Armament was one IX-inch Dahlgren, one 32-pdr, and one 24-pdr.  All of which were mounted on center pintle barbette mountings. Battery B, 2nd Missouri was posted here in June 1863.

Fort No. 2: Located off Cherokee Avenue and also manned by Battery B in June 1863.


Rectangular bastion fort with two IX-inch Dahlgrens, a 32-pdr, and a 24-pdr.  A cross-shaped blockhouse, with bunks for 150 men, in the interior.  A traverse covers the sallyport.  There are a couple of variations of this fort’s plan within the set. All show a rectangular bastion.  But the interior arrangement details differed.

Battery A:  This was a redoubt located between Forts No. 2 and 3.  It was off Arsenal Street. It appeared to have three gun positions.

Fort No. 3:  Maybe we call this a “half cross”?  The fort sat just south of Lynch Street.


The main bastion faced west and featured a position for a IX-inch Dahglren (which may not have been placed).  Covering the flanks were a pair of 32-pdrs.  Then a set of supporting bastions covered the sides and rear, each with a platform for a field gun. A blockhouse for 96 men sat within the rear face, flanked by outlets.  Battery F lived here in June 1863.

Fort No. 4: Similar layout as Fort No. 3, but off Shenandoah Street.


Similar armament and interior arrangements, but Fort No. 4 appears to be smaller along the faces.  Note the very detailed profile on the left.  Battery I occupied Fort No. 4 during June 1863.

Fort No. 5: Positioned on the north side of Lafayette Avenue, was another with triangular layout.


No indication as to the intended armament.  An asymmetrical layout with blockhouse and traverse in the interior. Battery A was in Fort No. 5.

Battery B:  Placed on Chouteau Avenue, and well advanced, was a redan in arrangement.

Fort No. 6: A trapezoid shape bastion fort south of Clark Avenue and covering the railroad entering the city at that sector.


The bastions were configured for two IX-inch Dahlgrens and two 32-pdr guns.  A blockhouse, that wrapped around a traverse, had 96 bunks.  Battery G manned Fort No. 6 in June 1863.

Battery C:  A simple battery placed on a rise adjacent to Fort No. 7, along Olive Street.  This appeared to be a three gun arrangement for field artillery.

Fort No. 7:  Shared a plan with Fort No. 6, but was advanced on Franklin Avenue (which we’ve discussed).  Battery E’s headquarters was in this fort in June.

Battery D: Located at the corner of the St. Charles Road and Grand Avenue.  This battery covered the cavalry remount depot.  Another three gun battery.

Fort No. 8: North of the St. Charles Road (Cass Avenue), this was an enclosed redan with two bastions:


The one bastion (left side, and what would be the north end of the fort) was setup for a IX-inch.  The other bastion had a 32-pdr.  Arrangements included three platforms for field guns. The blockhouse, which was “w” shapped, could house 200 men.  Battery E also manned this fort in June 1863.

Fort No. 9:  With a similar layout as Fort No. 8, this covered Natural Bridge Road, which entered the city from the northwest.


Fort No. 9 had two 32-pdrs in the bastions along with three platforms for field guns.  It boasted a fully formed caponiere.  The w-shaped blockhouse could house 200 men (two full companies according to the diagram). Two outlets were covered by two traverses, which contained magazines. Fort No. 9 was assigned to Battery C.

Battery E: On the opposite side of Natural Bridge Road, this two gun battery complemented Fort No. 9.

Fort No. 10: Located west of Bellfontain Avenue, this was another quadrilateral fort:


The four bastions supported a IX-inch Dahglren, a 32-pdr, and two 24-pdrs.  The rectangular blockhouse had 40 bunks.  Battery H manned this fort in June 1863.

Battery F: A two gun position that complemented Fort No. 10.

And that was the right end of  the line, just a few blocks from the Mississippi River.  I’m not aware of any surviving remains of these forts.  Even by 1870 the city was moving west and taking over what had been open fields in 1863.  So what we have to work with, for history’s sake, are these engineers plans and maps.  And what we see in the plans is much of Mahan’s teachings directly applied.


Fortification Friday: Complex “Intrenchments” and complexity fortification history

Earlier in this series, we looked at a class of fortification that Mahan labeled “simple fortifications.”  These included some well recognized – and some often misidentified – fortification layouts… “the Right Line; the Redan; the Lunette, or Detached Bastion; the Crémaillère, or Indented Line; the Priest-Cap, or Swallow-Tail; the Redoubt; the Star Fort; and Bastion Fort.”  And these were, for emphasis, “simple” in relative terms in regard to the level of effort required for the engineer to design the works.  Briefly, the simple entrenchments (or, if you prefer, fortifications) allowed the engineer to focus simply on a single point to be defended or single intended purpose… simply… for sake of redundancy.

But if there are simple entrenchments, there must be complex ones also, right?  Indeed.  And how do we define those complex entrenchments… or as they were called in Mahan’s day “intrenchments?  Well… as with many other things, Mahan avoided a specific definition.  Almost as if he wanted the cadets to focus more on the practical application than the theory.  But we can derive a general definition of “complex” from the description of the forms constituting these arrangements:

Lines or Complex Intrenchments.

Dispositions made to cover extended positions, and which present a front in one direction to the enemy, are termed Lines.  There are two classes of lines – Continued Lines, and Lines with Intervals.  Continued lines present no openings through which the enemy can penetrate except the ordinary outlets.  Lines with intervals consist of detached works, which are enclosed partly, or entirely, throughout their perimeters, arranged in defensive relations with each other; and presenting wide intervals between them defended only by their fire.

Implied here are three notions.  First, that complex entrenchments are actually a super-set of simple works arranged to present a front.  Second, that complex entrenchments are, as an aggregate, not just defending a salient point of importance, but rather the whole of an area.  Lastly, complex entrenchments, as the title “lines” implies, are erected to bar an adversary from approaching along a broad front.  These presumptions are reinforced by the second introductory paragraph from Mahan:

The same general principles apply to lines as to other intrenchments; but, from their great extent, they usually receive a slight relief, and the simplest angular figures are adopted for their plan.  In laying them out, the engineer should avail himself of all the natural obstacles presented by the position, so as to diminish the labor of erecting artificial ones.

See how this becomes counter-intuitive?  Complex entrenchments should, according to Mahan, be refined with simple angles of defense and fewer ancillary obstacles.  And from the perspective of the historian studying fortifications of the Civil War to latch onto.  Mahan feared exponential growth of labor requirements that might come from very complex arrangements.   And to that point, let me skip ahead to the last passage from the chapter on complex entrenchments:

Besides, a very capital objection in war, the time and labor required to throw up so many works are altogether beyond what can be disposed of in the ordinary circumstances of an army.

The emphasis is in the original –  “a very capital objection in war.”

You see, this is the point at which we must start reconciling what we know of field fortifications as a function of military science with what we know of the same fortifications as a described from wartime correspondence and observed with the surviving works.  Indeed, if one studies the accounts and walks along the surviving works, there are serious questions about how much of Mahan’s teaching shows up on the battlefield.  Sure, we see star forts, bastions, and redans at some places.  But how do we account for the entrenchments scattered about Virginia, particularly from the Overland Campaign?  (And mention Northern Georgia and a plethora of other places, but I’m selecting a handy point of reference here.)  The works at the Wilderness, Spotslyvania, and North Anna seem to be contradictory, in some places by small increments but at others with a wide gap, to Mahan’s teaching.

And this requires us, as historians, to recognize military science is not a fixed field of study.  Like any other profession, military science evolves, changes, and re-invents.  It is ever changing, even while reliant on core principles.  And with that in mind, we must lay Mahan’s pre-war teachings beside his post-war revisions, to the same manual of study.  Furthermore, we must also pull in the post-war manuals, such as Wheeler’s, which I much prefer, as additional perspectives.  It is vital to understand not only that military science was applied on the battlefield, but it also evolved due to its application on the battlefield.  We’ll see, as I progress along this thread of posts, how Mahan’s construct of “simple and complex” field fortifications would transition into Wheeler’s “simple, complex, and hasty” fortifications…. and that’s being overly simplistic.

There in lies the complexity when studying these complex entrenchments.  There is much a “point in time” to consider.  Not so much that manuals needed to be re-written, but that the re-writing was derived from experience derived from the very occurrences being studied.

I’ll go one further.  It is not enough that we recognize that military science evolved, offering a new approach to the application of field fortifications.  We should also seek out the drivers that caused that evolution.  Now we might lay this at the alter of the rifled musket.  But I’d challenge that long held belief a bit.  If this was all due to accurate, high-velocity projectiles, wouldn’t the natural evolution be towards thicker, stouter, more resilient works?

I say there’s more to it than just the mine ball and Hotchkiss shells.  And that something had to do with the point Mahan cited – time and labor.  In my opinion, the more important driver on military science were the advancements of technology that translated to better logistics and communications.  Those, by application, translated to operational mobility which far surpassed that of previous generations of warfighters. Then by extension, that gave the battlefield commander more resources to apply to the situation. You see, in order to add more complexity to those complex entrenchments, one must afford more time and labor.

OK…. I’m tipping my hand to a conclusion for which I’ve not presented the evidence.  To do that, we must first explore Mahan’s complex entrenchments, or lines, in detail.

(Citations from Dennis Hart Mahan, A Treatise on Field Fortifications, New York: John Wiley, 1852, pages 69 and 75.)

Fortification Friday: As Wheeler would say, “Loopholes are not just for blockhouses”

As we continue to compare and contrast the pre-war writings of Dennis H. Mahan with the post-war instructions of Junius B. Wheeler, let’s move from arrangements for the artillery to that of the infantry on the parapet.  Mahan, like his contemporaries, left the infantry on a bare parapet, with a firing step on the banquette that would allow them to step-up to the crest and fire over.  Little else was deemed necessary.  But experience of the Civil War indicated something more was indeed necessary.   Wheeler discussed this under the heading of “loopholes”:

Loop-holes.  – Troops on the banquette, when in the act of firing their pieces, are frequently exposed to the fire of the enemy’s sharp-shooters.  Under these circumstances, expedients must be devised to protect the men, without interfering with their fire.  The expedient which is most generally used, is that of an improvised loop-hole.  The loop-hole is made, in this case, by arranging two or more rows of sand bags, placed upon the parapet and filled with earth, so that the top row will be higher than the men’s heads, and so as to leave intervals between the bags in the lower rows, through which the men can aim and fire their pieces.

Figure 28 illustrated this arrangement:


Let’s walk through this passage, as it offers another glimpse into the changing doctrine applied to the battlefield.  Right from the start, we see something “non-Mahan” as a condition.  In those pre-war days where the Napoleonic battlefield framework was in play, musketry was generally used in mass.  Volley fire, by attacker and defender, was the expected means of delivering those lead projectiles.  In that framework, working a musket into a gap in sandbags would slow down the delivery of a volley.

But Wheeler alluded to a change in how musketry was used.  Instead of massing fires in volleys, the Civil War armies employed much more individual fires.  Skirmishing, of course, took on greater importance.  And in these field fortifications, that translated to sharpshooting.  More likely the attacker would employ this means of attriting the defender, instead of attempting a rush of the works.

This is not to say nobody ever thought of putting sandbags on the parapet before the Civil War (or headlogs, which we’ll circle back to).  But this is to say changes in the way musketry was delivered brought out a need to employ this feature (loopholes) as a standard fit on the parapet.  Wheeler and his contemporaries didn’t invent the sandbag loophole.  They simply introduced it to meet an evolving requirement.  Yes, “innovation” does not always mean “invention.”

There were other ways to setup a loophole on the parapet of course:

Gabions are also used for a similar purpose.  The gabions are placed in pairs upon the parapet and filled with earth, each pair being separated from the adjacent pair by an interval of about two inches.

And… field experience gave us even more options:

A contrivance adopted in the war of 1861-5, was quite effective for the same purpose.  Skids were placed upon the parapet, with notches cut in them.  A heavy log was placed on the skids, occupying a position parallel to the interior crest and just in contact with the superior slope.  Notches were cut in the underside of this horizontal log and these were used as loop-holes.  The openings to the exterior were made as small as possible, and in some cases were protected by small patches of boiler iron spiked upon the log.  When exposed to artillery fire, earth was banked against the log.

We often hear this or similar arrangements called a “head log” in the writings of veterans.  I am most curious that Wheeler didn’t use the term.  And even more curious why Wheeler didn’t include an illustration!  At any rate, he continued with this description, naming an “innovator” from the late war:

A wooden loop-hole was devised by Lieut. King (now Major) of the United States Engineers, which was used in 1864.  It was practically a wooden hopper made of boards, placed upon the superior slope of the parapet, and covered with earth.  The splay of the sole and the angle of the cheeks were made to suit the field of fire required.

The officer mentioned was Lieutenant William R. King.  Brett Schulte has King’s report on Beyond the Crater, and a detailed report it is.  The accompanying illustration matches to Wheeler’s description.  For brevity, I’ll refer you to Brett’s excellent site.

Wheeler continued, with detailed requirements for these loopholes:

The exterior orifice of a loop-hole for musketry should be made as small as possible.  A width of two inches and a height of five, is sufficiently large for ordinary purposes.  The sides are sloped, and an inclination given to the bottom and top, according to the field of fire which is to be swept.

Now what is good for the musket should also be good for the cannons, right?  Of course:

Embrasures are sometimes protected in a manner similar to this arrangement for loop-holes.  Timbers are laid across the embrasure, covering the throat, leaving only room for the muzzle of the piece.  These timbers are then covered by sand bags, by fascines, etc., to make them shot-proof.  Sometimes the embrasure is filled with sand bags or fascines to mask it, these things being quickly removed when the embrasure is needed for use.

Thick wooden shutters, made bullet-proof, and placed on vertical axes, and iron shutters swung on horizontal axes, have both been used to close the throat of the embrasure.

In some cases, timber supports were extended back from the parapet and a covering of timber and earth placed upon them, protecting the gun from vertical and plunging fire.  A gun thus sheltered is said to be case-mated.

Again we see the factor driving all this “innovation” and change – different types of fire were employed.   Individual musketry … sharpshooting as it may be called… brought out the need for protection on the parapet.  Vertical and plunging fire, which I have written about before, brought out the need for overhead protection.  No new inventions are introduced here, rather the innovation lay in the way existing practices were employed.

(Citations from Junius B. Wheeler, The Elements of Field Fortifications, New York: D. Van Nostrand, 1882, pages 126-8.)