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Post by TRK on Jul 4, 2007 10:36:37 GMT -5
Mark, on the old Alamo de Parras site in August 1999, Jake Ivey wrote a commentary on his interpretation of the March 1977 archaeological excavation of part of the area of the palisade (http://www.tamu.edu/ccbn/dewitt/adp/central/forum/forum40.html#south_wall_3). That excavation uncovered evidence of two parallel ditches, about 6' apart, associated with the palisade. In brief, the northern ditch was about 2.3' wide and 1.5' deep, while the southern ditch was described by Ivey as "ca. .75 feet wide (9 inches), with a U-shaped cross-section and a row of irregularly-spaced posts placed along its south side." (Boldface added for emphasis) Jack D. Eaton, who wrote the official report of the dig (http://www.tamu.edu/ccbn/dewitt/adp/history/archaeology/excavations/title.html), argued that both ditches held posts: i.e., there were two parallel palisades with earth fill between them. Conversely, Ivey maintained that the southern ditch was the location the palisade, while the northern ditch was probably dug to provide earth for a firing step along the palisade.
Concerning that northern ditch, Ivey wrote that it was "a space where the defenders could step down to get their heads below the firing slots left in the palisade wall -- firing slots that were protected for part of their height by the posts set outside the southern trench. You protect this single wall of logs with a packed earth padding against its exterior, taken from a ditch that, if dug on the outside of the defenses, adds a further defensive ditch as well."
If we accept Ivey's argument that the palisase comprised but one row of posts, I'm having trouble picturing how the row of "posts set outside the southern trench" looked, and what purpose they served. Ivey seems to be saying these posts were positioned at irregular intervals close to the south face of the palisade (but doesn't say how closely positioned these posts were, or how far they were from the palisade), and that they were shorter in height than the palisade. What purpose would the posts have served, particularly if Ivey is theorizing that there was an embankment of rammed earth on the palisade's southern face? From your knowledge of Ivey's unpublished book on the Alamo, can you shed any light on this?
Tom
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Post by billchemerka on Jul 4, 2007 12:04:25 GMT -5
Here's some additional info on the topic/questions at hand:
As Jake wrote on p. 95 of Alamo Anthology: From the Pages of The Alamo Journal (Eakin Press, 2005): "...other than a graphic representation by Theodore Gentilz, in a painting with innumerable other errors, [Jack] Eaton and [Herbert] Uecker have no documentation of any sort to support the idea of a double-row stockade filled with earth, which also violates basic military principles and common sense, while the single row stockade is shown on the maps of Ignacio Labastida and Jose Juan Sanchez Navarro, mentioned in Filisola's study of the Texas War and on Sanchez-Navarro's index to his map, fits the archeological evidence, and matches standard military practice. It is clear that Eaton and Uecker's description of the stockade along the face of the Alamo defenses cannot be accepted."
In his excellent essay in the book, Ivey devotes even more analysis to the aforementioned location along with the descriptions for every outer section of the Alamo's defenses.
However, I look forward to Mark's visual recreation of the location in his forthcoming book.
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Post by marklemon on Jul 4, 2007 22:44:30 GMT -5
Mark, on the old Alamo de Parras site in August 1999, Jake Ivey wrote a commentary on his interpretation of the March 1977 archaeological excavation of part of the area of the palisade (http://www.tamu.edu/ccbn/dewitt/adp/central/forum/forum40.html#south_wall_3). That excavation uncovered evidence of two parallel ditches, about 6' apart, associated with the palisade. In brief, the northern ditch was about 2.3' wide and 1.5' deep, while the southern ditch was described by Ivey as "ca. .75 feet wide (9 inches), with a U-shaped cross-section and a row of irregularly-spaced posts placed along its south side." (Boldface added for emphasis) Jack D. Eaton, who wrote the official report of the dig (http://www.tamu.edu/ccbn/dewitt/adp/history/archaeology/excavations/title.html), argued that both ditches held posts: i.e., there were two parallel palisades with earth fill between them. Conversely, Ivey maintained that the southern ditch was the location the palisade, while the northern ditch was probably dug to provide earth for a firing step along the palisade. Concerning that northern ditch, Ivey wrote that it was "a space where the defenders could step down to get their heads below the firing slots left in the palisade wall -- firing slots that were protected for part of their height by the posts set outside the southern trench. You protect this single wall of logs with a packed earth padding against its exterior, taken from a ditch that, if dug on the outside of the defenses, adds a further defensive ditch as well." If we accept Ivey's argument that the palisase comprised but one row of posts, I'm having trouble picturing how the row of "posts set outside the southern trench" looked, and what purpose they served. Ivey seems to be saying these posts were positioned at irregular intervals close to the south face of the palisade (but doesn't say how closely positioned these posts were, or how far they were from the palisade), and that they were shorter in height than the palisade. What purpose would the posts have served, particularly if Ivey is theorizing that there was an embankment of rammed earth on the palisade's southern face? From your knowledge of Ivey's unpublished book on the Alamo, can you shed any light on this? Tom Tom, First of all, let me say that I accept Ivey's overall description of the palisade construction and arrangement. No matter what Gentilz shows in his painting, Eaton is mistaken to believe that an infantry firing position could be serviceable which consisted of twin rows of posts set 6 feet apart and filled with earth. It just is not practicable for men to fire across a 6 foot wide barricade. They would only be able to fire at medium to maximum range, as lowering their barrels to fire at close range attacking infantry would not be possible. In order for them to fire down at all at an attacker, they would have to mount the top of the parapet, just like Filisola relates they did at the north wall, with disasterous results. In addition, Jake's description of the single palisade wall is correct in general theory. This type of defensive feature is seen frequently in the military manuals of the 19th century, i.e.: Mahan. However, I part ways with Jake ever so slightly about the specific arrangement of the palisade as regarding the loopholes. He seems to say (and I've read this three of four times in a row to be sure) that the south ditch measured "about 9 inches wide", into which posts of "about 9 inches thick" were placed. He then goes on to say that another row of posts were placed "at rough intervals of about two feet against its exterior..." These exterior posts at rough two foot intervals were supposed to be about two feet shorter than the higher ones, which were about 8 feet high from ground level to their tops. The pupose of these exterior posts (which would have been six feet high from ground to their tops) was that they were to serve as "loopholes." In other words, the riflemen inside the pailsade would place their rifles out of the gap between the shorter "exterior" posts, and the taller ones on either side, rest the rifles on the tops of the short posts, and fire. The trouble (and it is a rather small point) with this arrangement is that with a ditch of 9 inches in width, with posts set into them of nine inches in width, there is no room to then place others against them on their exteriors. The ditch would have to be some 18 inches wide. And while I have seen a single row of defensive pailsade in various military manuals, I have not yet seen a single row palisade with others set at intervals against the outside of the row. The same purpose may be obtained by using just one row of posts, and having the post at every two foot interval cut two feet shorter. This way, you have your posts, about 9 inches wide, set into your 9 inch wide ditch, and at the same time you have your "loopholes" as a result of the shorter sections. This is the way I have depicted the palisade, with shorter posts at about two foot intervals, as per Jake, but with the shorter posts set IN LINE with the taller ones, not out front. I will have to revisit Eaton's report, but unless he states that he sees a nine inch south ditch with occasional post holes out front and against the main line, I'll stick to my version. Ivey is not saying that there WAS an embankment of earth against the exterior of the palisade, he was saying that there was supposed to be one there. In actual practice, the Mexicans never completed the ditch which ran eastward from the lunette towards the palisade. As the ditch neared the palisade, its depth got progressively shallower, until it met the ground level, after having covered only about 20 feet of the palisade front, This means that only the same length of palisade (20 feet) was able to be covered by this protective outer embankment(at its western end), leaving the remainder of the 115 foot pailsade exposed. This is why the Texians elected, rather than complete the ditch, to simply drag a line of cut trees in front of the palisade to form an abatis. Hope this helps... Mark
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Post by stuart on Jul 5, 2007 1:05:41 GMT -5
The passage by Ivey in p91 of Alamo Anthology is a little clearer than the Alamo de Parras version:
"The northern ditch was about 2.5 feet wide and 18 inches or so of its depth survived. The second trench, 6 feet south of the first, was much narrower, and consisted of a U-shaped ditch about 9 inches across and 18 inches deep, with a series of post molds at about 2-foot intervals across its south face."
He then goes on to refer to a cross-section illustrated on p161 of an 1882 "Manual of Fortification" by J.B Wheeler to justify this business of posts set forward of gaps in the main stockade, and also cites Mahan p93.
I agree that it all sounds very odd but I have access to neither Wheeler nor Mahan (who was contemporary with the Alamo) so can't really take this any further than that.
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Post by marklemon on Jul 5, 2007 1:36:52 GMT -5
The passage by Ivey in p91 of Alamo Anthology is a little clearer than the Alamo de Parras version: "The northern ditch was about 2.5 feet wide and 18 inches or so of its depth survived. The second trench, 6 feet south of the first, was much narrower, and consisted of a U-shaped ditch about 9 inches across and 18 inches deep, with a series of post molds at about 2-foot intervals across its south face." He then goes on to refer to a cross-section illustrated on p161 of an 1882 "Manual of Fortification" by J.B Wheeler to justify this business of posts set forward of gaps in the main stockade, and also cites Mahan p93. I agree that it all sounds very odd but I have access to neither Wheeler nor Mahan (who was contemporary with the Alamo) so can't really take this any further than that. Well, I think that the deciding factor must be the archeology. I need to check Eaton's report in this regard. I should think that if there was such a staggered positioning of posts, even at intervals, this would be apparent in the ground, as postholes leave a pretty clear mark. I have read Eaton's report in the past, and honestly don't remember him describing any such arrangement, but I certainly may be mistaken.
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Post by stuart on Jul 5, 2007 3:41:26 GMT -5
I’m also a little bothered by that 2 foot spacing, which seems rather close for loopholes. It may be explained either or both of those manuals, but its not something I’ve come across before. Could the wall have been formed of logs laid horizontally rather than planted vertically, and retained in place by those external vertical posts at 2 foot intervals?
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Post by TRK on Jul 5, 2007 7:36:07 GMT -5
First of all, let me say that I accept Ivey's overall description of the palisade construction and arrangement. No matter what Gentilz shows in his painting, Eaton is mistaken to believe that an infantry firing position could be serviceable which consisted of twin rows of posts set 6 feet apart and filled with earth. It just is not practicable for men to fire across a 6 foot wide barricade. Thanks for your reply, Mark; indeed, it helps. I tend to agree with the single-row palisade theory. The archaeology certainly seems to support Ivey's view. I also agree with you that on the surface, it doesn't make sense that the builders of the palisade would have taken the effort to dig, in addition to the 9" ditch for the main line of the palisade, separate post holes about every two feet for posts positioned just outside of the ditch [NOTE: The rest of this sentence is a later revision], if those posts were meant to create loopholes. Indeed, why not just place the shorter posts in line with the longer ones? I can't envision any advantage to having the shorter posts placed out front, in terms of traverse, aiming, freedom of movement, etc., of the defenders' rifles and muskets. Without anything other than supposition in support, I wonder if the separate postholes in front of the palisade ditch might represent something other than an 1836-era feature: for example, the vestiges of a previous fence spanning from the church to the Low Barracks, the line of which the palisade ditch happened to follow. Or, perhaps the posts were part of a structure to buttress or beef up the exterior of the palisade. I have Eaton's 1980 report in front of me, and it simply states that during the 1977 excavations, "traces of what appears to have been the edge of a second palisade trench were uncovered in Units 7 and 12. The remnant of this second probable trench is located 1.90 m. (6 ft.) south of the first trench, extending parallel with it, and is of the same orientation." Nothing about the depth and width of the trench; wouldn't you think that would have been worth reporting, for comparison with the dimensions Eaton gave for the other trench to the north of it? By the way, here's where you can download Dennis Mahan's Treatise on Field Fortifications: books.google.com/books?id=rSEKAAAAIAAJ&pg=PA45&dq=mahan+manual+fortifications+palisade&as_brr=1#PPA44,M1
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Post by Herb on Jul 5, 2007 9:16:12 GMT -5
Reading this, if I understand correctly the second line is six foot south of the palisade, could these shorter poles, have been upright supports for some envisioned horizontal retaining wall like a fascine, to hold the earth that was supposed to be provided by the ditch?
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Post by stuart on Jul 5, 2007 10:40:23 GMT -5
I think that’s the trouble with this one. Its not at all clear that the findings represent a single coherent structure. We all seem to be pretty well agreed that a line of vertical posts set 2 feet apart directly in front sounds more like some kind of buttressing for a wall of logs (or fascines) laid horizontally – the outer “ditch” being the foundation cut.
To my mind, and I’m greatly hampered by a lack of drawings, this raises two questions; was the outer structure unrelated to the fortifications as Tom suggests may have been a possibility, or was it the actual fortification line? I note that although what seems to have been regarded as the “main” ditch is some 6 feet north of this one there’s no mention of post holes there.
Stressing again that I probably haven’t got a complete picture, my reading of the evidence as presented by Jake Ivey per his article, is that the stockade was actually comprised of logs laid horizontally rather than planted vertically. This was braced on the outer side by vertical posts set at 2 foot intervals and perhaps on the inner side by dirt excavated from the northern ditch – although I’m not convinced by this. The immediate question which then arises is why was that (inner) ditch so substantial? Does it represent an initial fortification line which was cut and then abandoned, because the line was moved forward by 6 feet?
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Post by Rich Curilla on Jul 5, 2007 11:50:46 GMT -5
No matter what Gentilz shows in his painting, Eaton is mistaken to believe that an infantry firing position could be serviceable which consisted of twin rows of posts set 6 feet apart and filled with earth. It just is not practicable for men to fire across a 6 foot wide barricade. They would only be able to fire at medium to maximum range, as lowering their barrels to fire at close range attacking infantry would not be possible. In order for them to fire down at all at an attacker, they would have to mount the top of the parapet, just like Filisola relates they did at the north wall, with disasterous results. Just a thought on methodology in considering a *best of all possible worlds* realization of book field fortifications a-la Mahan by the Mexican military engineers: Aren't the folks who built the palisade on the south end the same folks who built the reinforcements on north wall? If so, why should we assume book precision on the south if they failed so miserably (as per Filisola) on the north, resulting in a fortification that a rifleman had to climb on top of in order to shoot down? I still adhear to the rule of human failing in a real world, resulting in a less-than-perfect fortification.
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Post by marklemon on Jul 5, 2007 11:58:43 GMT -5
We need to be careful about this point in the discussion, because it seems that we are agreeing to a suppostion based on a fact that is not stated. Eaton does not say in his report that, in the southernmost ditch there was anything that looked like a SECOND set of 2-foot spaced postholes up aginst the first ones. If he had said this, I'd be right there with Jake Ivey (with the vertical palisade featuring outer-attached shorter posts)or Stuart (a horizontally laid barrier butressed by 2-foot spaced posts). But failing this, we shouldn't start, I shouldn't think, to go off in that direction, as the available evidence doesn't support this arrangement. What we HAVE is, two ditches, one a couple of feet wide, and about 2 feet deep (allowing for alterations done to the 1836 ground level by later scraping of the plaza), and another narrower (9" wide) ditch, set 6 feet south from the first one. In defensive positions, trenches have the happy consequence of providing at least two benefits: they can provide protection , to varying degrees, by allowing the defenders to step down into them, thus lowering their profile, and secondly, they give us earth to build something else. In the case of single row barriers, such as that shown by BOTH Navarro and Labastida at the palisade area, this inner trench, and its dimensions, can really mean only one thing: It was dug, as per Ivey, to give a protected postion for the defenders to step into, but most importantly, it provided earth for a firing step. Jake has calculated this step to have been about 1.75 feet high, and about 2 to 2.5 feet wide. No outer ditch was ever completed, thus depriving the palisade of its protective embankment of earth (except for about 20 feet at the west end.) The 9 inch wide trench was far too narrow to be anything other than the cavity in which to place posts, or timbers. And, when one consults the manuals, both before and after this period, the upright, vertical arrangement seems to be pretty standard. SO, what I read from all this is that the palisade had:1) a 2 foot wide, roughly 2 foot deep trench running from the SW corner of the church to the SE corner of the Low Barracks, but set back about 6 feet from the ACTUAL corner-to-corner line. 2) a firing step, 1.75 feet high, and 2.5 feet wide, several feet to the south of this 2 foot wide tench, made from the earth excavated from this trench. 3) a vertically arranged palisade barrier, with 10 foot long posts set 2 feet into the ground, leaving 8 feet exposed above ground. Along this row, at intervals of two or more feet, were loopholes formed by simply cutting one of the posts 2 feet shorter. This would, when allowing for the 1.75 foot high firing step, give us an aperture, or loophole, of a little more than 4 feet high (4.25) which Jake tells me is the correct height for such things according to "the book." I am in close agreement with Ivey in his reading of the data, right up until he places those 2-foot spaced posts against the outer face of the main palisade. Here, he is engaging in supposition, which I don't yet see supposted by the facts. Unless and until we can locate any reference to a SECOND set of closely spaced postholes, I strongly support the "single-row theory."
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Post by marklemon on Jul 5, 2007 12:09:14 GMT -5
No matter what Gentilz shows in his painting, Eaton is mistaken to believe that an infantry firing position could be serviceable which consisted of twin rows of posts set 6 feet apart and filled with earth. It just is not practicable for men to fire across a 6 foot wide barricade. They would only be able to fire at medium to maximum range, as lowering their barrels to fire at close range attacking infantry would not be possible. In order for them to fire down at all at an attacker, they would have to mount the top of the parapet, just like Filisola relates they did at the north wall, with disasterous results. Just a thought on methodology in considering a *best of all possible worlds* realization of book field fortifications a-la Mahan by the Mexican military engineers: Aren't the folks who built the palisade on the south end the same folks who built the reinforcements on north wall? If so, why should we assume book precision on the south if they failed so miserably (as per Filisola) on the north, resulting in a fortification that a rifleman had to climb on top of in order to shoot down? I still adhear to the rule of human failing in a real world, resulting in a less-than-perfect fortification. The thing to remember about the north wall defensive position is that it wasn't finished ...the Mexican engineers may not have been the Queen's own, but they showed remarkable knowledge and skill, at least much more than they have heretofore been given credit for. The horizonally placed timbers, butressed by vertically set ones, and braced by angled posts, was perfectly sound engineering, especially in light of the fact that, due to obstructions all along the inner surface of that wall, they couldn't be placd anywhere else. The key fact is that these timbers and braces, both horizontal and angles, were meant to be covered by an earthen blanket, and, as you know, time precluded them from completing this task. I have no doubt that an inner banquette was planned, from which the defenders could fire. The added thickness of the wall occasioned by the added reenforcing, was just something that they had to live with. Unfortunately, without this banquette, it was something the Texians had to die with...
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Post by TRK on Jul 5, 2007 15:14:21 GMT -5
Reading this, if I understand correctly the second line is six foot south of the palisade, could these shorter poles, have been upright supports for some envisioned horizontal retaining wall like a fascine, to hold the earth that was supposed to be provided by the ditch? Just to reinforce what Mark so ably described, the line of postholes spaced about two feet apart, as reported by Ivey, were aligned close to the south edge of the southernmost, or 9-inch-wide, ditch. I don't know if Ivey's gone on record as to the average distance between those approx. 2'-on-center postholes and the southern edge of the 9"-wide ditch. It turns out Eaton's report on the excavations that located parts of the palisade ditches is online: table of contents here: www.tamu.edu/ccbn/dewitt/adp/history/archaeology/excavations/toc.htmlPlan showing the location of the ditches here. Notice that the 9"-wide, southernmost ditch is indicated only by a single line; thus, it doesn't convey the fact that the ditch was about 9" wide: www.tamu.edu/ccbn/dewitt/adp/history/archaeology/excavations/figures/fig3.html
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Post by stuart on Jul 5, 2007 15:53:02 GMT -5
I've had a look at that copy of Mahan which has been digitised by Google. It clearly isn't the same edition used by Ivey as the page number quoted doesn't work.
There is however a good description of how to contruct a stockade - and loophole it from page 57 onwards. There is no mention at all of this curious business of posts set forward of it at 2 foot intervals.
Nor of course is there any mention of them in Eaton's excavation report as above, yet Ivey's article is very specific in describing not a theoretical line of posts arising from some mistunderstanding of Mahan's (or Wheatley's) text, but the discovery of post holes.
Therefore I have to return once again to the point. Either the post holes (and posts) do not exist in which case we have no reason to doubt a stockade of upright posts. Or they do exist despite Eaton's published report being silent and were used to buttress a wall of horizontal logs laid in a sill trench - which according to Gary Zaboley's drawings at least was what comprised the outer face of the north wall.
Incidentally, I've not read Mahan before, but was truly impressed with his common-sense and clarity. Its easy to see how he was able to exercise such influence over generations of officers
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Post by marklemon on Jul 5, 2007 17:29:51 GMT -5
This business of a horizontally laid barrier at the south just isn't supported by the evidence. First, there would, if this were the case, be no reason at all to dig a two foot deep "sill trench" for posts laid down horizontally. This is because the strength gained when vertical posts are buried in such a manner, does not apply with ones laid down...this is because the posts laid down are not integral to the ones above or below it, and are just laying on top of one another. One then needs to brace and hold them together somehow. This is done by holding them in at BOTH sides, not just the front, as a pile of posts braced only from one side just falls down. So if we had such an arrangement at the Alamo, Eaton would have found a shallow "sill trench" and evenly spaced postholes on EITHER side of this trench. Instead, he apparently found only the 2 foot deep single trench, and NO post holes, either at the front or rear of this trench, which effectively ruels out such an arrangement. Eaton would surely have mentioned this curious find if it had existed.
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