yep, and super flat.
when i attempted to spall a few months ago i had the stone suspended (no support) and was using a hard hammerstone. it resulted in spalls with large bulbs of percussion.
i need to go back to that rock and attempt it with the base supported. i still have a few of them left.
Regarding the flatness, the nodule is resting on a pad, on my thigh. The pad acts as a bit of a fulcrum. In other words, the blow causes the broken portion to pull away from the nodule. And, the fulcrum pad, plus hand manipulation, cause the nodule to pull away from the broken flake.
Since the pad is soft, and yielding, it causes the break to act differently than if I had used a stone anvil. If I had used a stone anvil, the break probably would have reached the center, and hinged. The soft pad, used as an anvil, allows the break to continue under the surface, while not stopping, or hinging. The give of the anvil may lengthen contact time, which may lead to a larger flake.
This is similar to the idea that Catlin outlined, after encountering "Apaches" in the far west, between the 1830's and the 1840's, I believe in a remote mission settlement. The details that Catlin explained, about their flintknapping, are not even understood by many modern flintknappers.
Here is the entire account, published in 1867, but probably witnessed between 1830 and 1840>
"Every tribe has its factory, in which these arrow-heads are made, and in those, only certain adepts are able or allowed to make them, for the use of the tribe. Erratic boulders of flint are collected (and sometimes brought an immense distance), and broken with a sort of sledge-hammer, made of a rounded pebble of horn-stone, set in a twisted withe, holding the stone, and forming a handle."
"The flint, at the indiscriminate blows of the sledge, is broken into a hundred pieces, and such flakes selected as, from the angles of their fracture and thickness, will answer as the basis of an arrow-head."
"The master workman, seated on the ground, lays one of these flakes on the palm of his left hand, holding it firmly down with two or more fingers of the same hand, and with his right hand, between the thumb and two fore-fingers, places his chisel (or punch) on the point that is to be broken off; and a cooperator (a striker) sitting in front of him, with a mallet of very hard wood, strikes the chisel (or punch) on the upper end, flaking the flint off on the under side, below each projecting point that is struck. The flint is then turned and chipped in the same manner from the opposite side, and so turned and chipped until the required shape and dimensions are obtained, all the fractures being made on the palm of the hand."
"In selecting a flake for the arrowhead, a nice judgment must be used, or the attempt will fail: a flake with two opposite parallel, or nearly parallel, planes is found, and of the thickness required for the centre of the arrow-point. The first chipping reaches near to the centre of these planes, but without quite breaking it away, and each chipping is shorter and shorter, until the shape and the edge of the arrow-head are formed."
"The yielding elasticity of the palm of the hand enables the chip to come off without breaking the body of the flint, which would be the case if they were broken on a hard substance. These people have no metallic instruments to work with, and the instrument (punch) which they use, I was told, was a piece of bone ; but on examining it, I found it to be a substance much harder, made of the tooth (incisor) of the sperm-whale, which cetaceans are often stranded on the coast of the Pacific. This punch is about six or seven inches in length, and one inch in diameter, with one rounded side and two plane sides ; therefore presenting one acute and two obtuse angles, to suit the points to be broken.
This operation is very curious, both the holder and the striker singing, and the strokes of the mallet given exactly in time with the music, and with a sharp and rebounding blow, in which, the Indians tell us, is the great medicine (or mystery) of the operation." (Last Rambles among the Indians, Catlin).
Catlin recognizes that certain skilled people were specialists, in arrowhead manufacture. He recognizes that stone was first broken up with mauls. He accurately describes the design of the stone maul. He describes the selection and shape of spalls, as opposed to waste materials. He describes the use of isolated platforms, which he calls "protuberances". He describes the length of the flakes being removed - falling short of the mid-line. He describes the size, and shape, of the flaker. He describes the effects of using the palm of the hand, as a rest, and how the elasticity of the palm prevents the stone from shattering.
Given that Catlin probably witnessed this, between the 1830's and 1840's, this should be one of the earliest, and most detailed accounts of Native American flintknapping, ever recorded. Also, this description predates the modern invention of the flintknapping baton, by almost one hundred years, since the flintknapping baton was invented by Barnes, during the 1930's, after long decades of hammerstone experimentation.
So, why isn't this account hailed as one of the best ABORIGINAL AMERICAN fintknapping accounts on record? First, Catlin died just after this account was published, during the late 1860's. Then, people could not fully understand the account.
The confusion probably hangs on these words,
"strikes the chisel on the upper end". If we interpret this to mean on the upper butt end, then the chisel would have been held vertically, and struck from above. And, this was actually depicted in illustrations, that were drafted up long after Catlin was dead.
But, Catlin subsequently wrote,
"flaking the flint off on the under side, below each projecting point that is struck."So, Catlin speaks of an "upper", and an "under". What if Catlin was referring to the upper end of the flaker, and the under side of the side of the stone, with regard to the flaking process being carried out? If so, then the process would have been analogous to a pressure flaking process, only the upper end of the flaker would have been struck downwards, and the underside of the stone, would have been detached. If this is the case, then it would match other descriptions of flaking, given by other observers. But, since this was not well understood in Europe, the entire account was pretty much laid aside by the end of the 19th century.