The Calaveras skull, front view. From Skeletal Remains Suggesting or Attributed to Early Man in North America.

In February of 1866 the Illinois-born blacksmith James Mattenson* decided to try his luck beneath Bald Hill in Calaveras County, California. There was a chance that the subterranean depths of the hill were streaked with gold, and to this end Mattenson sunk a mine shaft into the rock. For one hundred feet below the surface the hill was nothing but solidified lava, but fifty feet below that the hill was made up of interspersed layers of gravel and volcanic tuffs. Mattenson had little luck finding gold or any other precious metals, but it was there, one hundred and fifty feet below the surface, that he picked up something more precious than gold. Locked in the rock was a human skull, a vestige of humanity’s earliest days upon the earth.

*[Also reported as Matson, Mattinson, etc. I have opted for "Mattenson" for this essay, although the true name of the skull's discoverer seems to be a mystery by itself!]

Mattenson had found something that would be argued over by academics for years, yet he did not immediately recognize what he had found. At first the thought he had come across a petrified tree root, but it was enough of a curiosity to justify extracting it from the mine. Once Mattenson had exhumed the fossil he brought it to a man who lived in the mining town who, in turn, showed it to a local merchant named Scribner.

Scribner realized that what Mattenson had found was a human skull, and after cleaning it up a bit he sent it off to a physician named Dr. Jones in San Francisco. Jones was also astounded by Mattenson’s find, but the story did not truly take off until it gained the attention of California’s state geologist Josiah Dwight Whitney. When Whitney learned of the skull he visited the mine and determined that the skull had to be of Pliocene age, making it one of the oldest human fossils ever found.

Whitney’s conclusion did not seem unreasonable at the time. Other authorities had claimed to have found stone tools, like mortars and pestles, under hills in Calaveras County. Together these tools and the skull showed that humans had inhabited North America for as long, if not longer, as the fossil humans of Europe. Perhaps the New World was just as important to the story of human evolution as the Old World.

Whitney championed the authenticity and importance of the Calaveras skull, but not everyone was convinced by it. Other scientists were wary of a fossil that was not examined in situ by any reputable authority. How could the provenance of this skull be determined if it was simply plucked from the ground and passed around?

Young earth creationists were alarmed by the find, too. They asserted that the skull could not be more than 6,000 years old and probably had come from some unfortunate miner. Academics heaped scorn on this idea and denied that the skull had been planted in the mine by some unscrupulous person. An article in the Harvard Register, for instance, stated that the Calaveras skull “has been mercilessly assailed as a hoax, not on account of any suspicious circumstances attending its discovery, but because it was predetermined in the minds of many that man did not live at so ancient a time.” The authenticity of the skull would be determined by scientists, not zealots, and this sentiment was echoed in a later 1899 report by William Dall;

In the speaker’s opinion, the attempts on the part of unscientific persons of the vicinity to discredit the authenticity of the skull after it had attracted general attention were due to that spirit, unfortunately too common among ignorant persons, which leads them to disparage that in which they have no share. As the persons chiefly concerned made no attempt to utilize the discovery as a source of profit, and the coming of the specimen into scientific hands was due to circumstances which could not have been foreseen, the speaker believed that so far, no sufficient reason had been adduced for doubting the genuine character of the skull and its original situs below the lava; though the question of the coexistence of man and the extinct mammals whose remains have been found in the same gravels is entirely distinct and may reasonably be left open.

The criticisms of other anthropologists, however, could not be so easily swept aside. One of the primary critics of Whitney’s claims was the Smithsonian scientist W.H. Holmes, and key to Holmes’ analysis were objects found in the rock encrusted with the skull. When Mattenson removed the skull it was still partially encased in the material in which it was found and the surrounding sediment was removed with ease by Scribner. In it were found a few bones, a snail shell, and a shell bead.


The Calaveras skull, left side. From Skeletal Remains Suggesting or Attributed to Early Man in North America.

Whitney thought that the skull had bounced along a Pliocene river where it settled in sediments containing these tidbits, but Holmes disagreed. Rather than support the great age of the skull the assorted debris undermined it. The snail shell was from a modern type of snail and the shell bead looked just like those made by Native Americans. It was unlikely that remnants of the Pliocene would so closely resemble their modern counterparts, and there was nothing about the skull itself that would suggest it had come from deposits as old as Whitney supposed. As Holmes concluded;

It thus appears that the so-called Calaveras skull exhibits nothing in its character, condition, or associated phenomena incompatible with the theory of recent origin, and very much that may be justly construed as favouring that theory.

If the skull was of more recent origin, though, how did it get to the bottom of the mine shaft? It was a very curious case, and rather than weigh in on one side or another some anthropologists took an agnostic position and simply briefly mentioned what was known about the skull. Perhaps some later bit of evidence would arise to make sense of it all, but that evidence never seemed to turn up. That may have been for the best. As recognized by Robert Munro in his book Archaeology and False Antiquities, by the 1890′s the Calaveras skull had the potential to throw a monkey wrench into our understanding of human evolution.

Up until the 1890′s all of the fossil humans that had been discovered were very close in appearance to modern humans. The Neanderthals, for example, we originally considered by many authorities to be pathological or degenerate versions of the modern human type. Then came “Pithecanthropus” (now known as Homo erectus), a sort of “ape-man” that stood halfway between apes and humans. The problem was that Whitney had proposed the Calaveras skull as being older than the age hypothesized for “Pithecanthropus”, making the “ape-man” younger than the modern-looking human. How could a human with a brain large enough to be a philosopher, Munro asked, be older than the famous “ape-man” of Java?

There was something definitely wrong about the Calaveras skull, but it was not until the beginning of the 20th century that it was revealed for what it truly was. The skull had been planted as part of a hoax, and a very simple hoax at that. Accounts differ, but it appears that Scribner, the store owner in the mining town near Bald Hill, was one of the chief architects of the ruse.

The controversy had started as a simple prank. It was well-known in the town that Mattenson would dig a little deeper into his mine when things got dull, and Scribner decided to take advantage of this by placing a skull in the rock at the bottom of the mine. As expected Mattenson soon found the skull and showed it to a friend, but when that friend showed it to Scribner the shopkeeper kept his lips sealed. Perhaps, some wondered, Scribner meant to play a joke on Dr. Jones. If Whitney had not obtained the skull, however, the skull might have sunk into obscurity. Sources differ as to how Whitney procured the skull, but a letter from July 1866 shows that he had obtained it by that time. After that it’s history was recorded in academic journals.

Yet where did the skull come from? No one really knew. One sensational story said that the skull had belonged to a Native American horse thief killed by a mob. This is unlikely. From the condition of the skull it would seem that the horse thief would have been rather elderly and no mention is made of why the mob decided to deflesh the thief’s body just for a practical joke. It is more likely that the skull was taken from a nearby Native American burial site, but this, too, requires confirmation.

Unfortunately the details of the hoax, the parties involved, and the origins of the skull were never laid out in explicit detail. It was said that the hoax was well-known in the mining town in which Scribner worked, yet it has been extremely difficult to find a primary account of what occurred. Everything was funneled through journals and newspapers and it is difficult to separate the hearsay from the truth. That the skull was planted as a prank is a near certainty, but after that things get hazy.

In some ways the Calaveras skull controversy anticipated aspects of the more famous “Piltdown Man” fraud of the 20th century. Originally planted as a prank, the Calaveras skull took on a life of its own in the literature. Academics debated its importance (or lack of importance) to our own history, but as anthropologists learned more the more out of place it seemed. Then, after several decades of debate, it was revealed to be a hoax and practically disappeared from discussion. (Some creationists, though, used the embarrassment to try to undermine scientific understanding.) Perhaps some ambitious historian can eventually uncover more about the complicated origins of this controversy, but for now it appears to be a forgotten footnote in the history of science.


  1. #1 chezjake
    May 5, 2009

    I’m led to wonder if Scribner’s inclination to pull a “prank” had anything to do with a well known joker who just happened to be living in that area for a couple years just before the finding of the skull — Mark Twain.

  2. #2 Blake Stacey
    May 5, 2009

    Awww, I was gonna make a joke about the celebrated jumping skull of Calaveras County. . . .

  3. #3 Laelaps
    May 5, 2009

    Jake; That has been suggested, although it isn’t known for sure. It would be wonderful if someone could dig up some letters or journal entries by Scribner (or those who knew him) about the hoax, but as far as I know no such evidence has been found. Most of what I found were reports cobbled together from different sources; when I started writing this post I hoped for a more definitive resolution!

  4. #4 neil
    May 6, 2009

    Curiously, “calaveras” is Spanish for “skulls”…

  5. #5 Vasha
    May 6, 2009

    Bret Harte wrote a less-than-reverent ode to this relic: “To the Pliocene Skull”.

  6. #6 Brian Schmidt
    May 8, 2009

    Good reminder about extraordinary evidence here.

    Speaking of that type of evidence, and no offense to the H. floriensis discoverers, but has there ever been third-party analysis to exclude a hoax? I know science normally assumes good faith, but extraordinary evidence like Ling Bua might need to rule everything out. (And I know the fossils were examined by a skeptical scientist, but I don’t know whether he took any steps to rule out fraud).

The site is currently under maintenance and will be back shortly. New comments have been disabled during this time, please check back soon.