Scientific American on the "Plesiosaur" of Patagonia

The July 1922 issue of Scientific American (Vol. 127 issue 1) included an article on page 21 titled "An Antediluvian Monster - Is the Argentine Plesiosaurus a Fake or a Scientific Marvel", by Leonard Matters.

Below is an image with the article.

An Antediluvian Monster. Scientific American

Below I quote it fully, just for the record, of course outlines the case and gives us the impression that Onelli's story was a indeed fake:

"Whatever may be the opinion in scientific circles —and it is one of scornful skepticism—the fact remains that the report of the existence in Argentina of a living specimen of a race of mammoth reptiles, supposed to have been extinct for millions of years, has excited intense interest. Every scientist of note has scoffed at the idea, but, headed by Dr. Clement Onelli, Director of the Zoological Gardens at Buenos Aires, there is a large body of Argentine public opinion strongly of opinion that a member of the plesiosaurus family will be discovered, alive or dead.
Dr. Onelli has disclosed to the press in Buenos Aires the fact that some time ago he received a letter from a American mining man down in Patagonia, reporting the existence of some monster, of a type well known to palentologists through fossil remains, but unknown to modern zoology. The American, a Mr. Sheffield, has been prospecting for gold along the Andes in the Tertitory of Chubut for many years, and Dr. Onelli says he knows him to be perfectly reliable. Mr. Sheffield wrote to the doctor stating that he had come across some enormous tracks near a lake. Bushes and undergrowth were trodden into the ground, and so deep were the tracks that they could only have been made by some living thing of ponderous weight. Continuing his account, Mr. Sheffield said: “I saw in the middle of the lake an animal with a huge neck like that of a swan, and the movement in the water made me suppose the least to have a body like that of a crocodile.”
Dr. Onelli has pointed out that Mr. Sheffield has given, for a layman, a remarkably accurate outline of the plesiosaurus, one of the mammoth reptiles that lived countiess years before the ice-age, and became extinct during that geological epoch in the world's history. Moreover, the report recalls more than one similar story of the existence in Patagonia of some strange feature, never yet clearly identified. Patagonia was undoubtedly at some time the habitat of mammoth beasts, and prehistoric man. Extensive fossil beds have been located, and scientific knowledge has been Widely enriched by the discovery of many kinds of extinct mammals and reptiles. Professor Frederic B. Loomis conducted an expedition through the Territory of Chubut in 1911, on behalf of Amherst College, and was successful in unearthing a petrified forest and, among other interesting fossils, the skull of a pyrotherium, an extinct elephantine creature.
There has long existed a romantic sort of idea that in the comparatively uninhabited parts of Patagonia, where certain forms of vertebrates are believed to have originated, a discovery would yet be made, of a nature that would stagger science—the finding of-the “missing link,” for instance, or more probably the capture of an actual living specimen of some supposedly extinct creature of antediluvian antiquity.
Palentologists and scientists in general have never been associated with such a belief, but nevertheless it has been a popular fancy, and has not lacked some degree of support among men whose opinion carries weight. In announcing the latest report to the public Dr. Onelli has recalled this interesting speculation. He was personally first attracted by the idea 25 years ago when he was down in Patagonia. On the shores of White Lake there then lived a Chilean farmer who declared that often at night a strange noise could be heard, as though a cart were being dragged over the pebbly shore. It was asserted that on moonlight nights a huge beast could be seen in the lake. It had a long reptilian neck which rose high above the water, but when disturbed it would at once dive and disappear in the depths.
Ten years after hearing of the apparition in White Lake, Dr. Onelli heard of the discovery made by a Norwegian engineer named Vaag, who was a member of the commission of demarcation of the boundary between Argentina and Chile. Mr. Vaag gave the name of River Tamango to a waterway flowing from the Andes, on whose banks he found the remains of some great beast, and the tracks of a creature that probably resembled the plesiosaurus. Later on, in a cavern, further south at Ultima Esperanza (Last Hope) there were found the remains of a hide and many bones of a great quadruped. The condition of the hide and the fact that the bones were conserved in a gelatinous condition, gave rise to the belief that it might be possible to find a similar beast alive. These interesting discoveries led to a number of expeditions, to which popular imagination at least attracted the objective of looking for a surviving specimen of the mammoth age, even if the scientists themselves had no such belief in the idea. These expeditions worked in different parts of Patagonia, and made interesting discoveries, though credence in the they found nothing to warrant any popular theory supposing the existence of zoological phenomena.
This, in brief, is the history behind the most recent report made on the authority of Dr. Onelli. Science in general utterly discredits the suggestion that a plesicsaurus, or anything like the extinct reptile, is still alive, and the many scornful comments on Dr. Onelli’s report leaves it doubtful whether scientists admit even the possibility of there being in Patagonia some unknown animal of large proportions. It has been hinted that the creature with the long swan-like neck is in the sume class as the sea-serpent, and is really born in a bottle. However, the refusal of scientists to take Mr. Sheffield’s story and Dr. Onelli’s theory as credible, has not prevented the doctor and the Argentine people getting deeply interested in a proposal to fit out an expedition for the capture of the creature, alive or dead.
So seriously has the idea been taken up that a rather amusing development has followed. Dr. Albarrin, President of the Society for the Protection of Animals, has demanded that the Minister for the Interior shall stop the expedition, under Law No. 2,786, which prohibits the hunting and destruction of rare animals. Dr. Albarrin urges that if there should still exist a plesiosaurus, then Argentina possesses a scientific marvel of immense value, and it should neither be killed nor captured, but should be allowed to enjoy to the full the liberty it has had over millions of years. The worthy doctor claims that it would be more humane and creditable to Argentine culture to leave the creature where it is and let it reproduce its species."

You can Read it online and see what this magazine looked like over 103 years ago.

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2025 by Austin Whittall © 

Not a Plesiosaur - 1922 articles about Onelli's "strange animal"

Not all were fooled by the media's preposterous claim that there was a living plesiosaur in some Patagonian lake. There were many articles published that refuted his claim. One, published by the Ottawa Field-Naturalists' Club is copied below. It appeared in The Canadian field-naturalist, published in May 1922 (Vol. 36, No. 5, p. 97) by

Notice the incorrect dating used at the time (3 million years for the Cretaceous vs. at least 65 Ma as we now know). You can read it online, below we transcribe the article:

Not a Plesiosaur. — The newspapers of late have had a great deal to say about the strange animal which has been seen in Patagonia, and in nearly every case it is spoken of as a plesiosaur. What the strange animal will prove to be, the writer would not attempt to guess, but a few remarks about plesiosaurs will show that there is little chance of Prof. Onelli capturing a live plesiosaur.
The plesiosaur lived from Triassic to Cretaceous times, but not a bone of any genus of the order has been found in rocks of more recent age than Cretaceous. This means that plesiosaur has been extinct for more than three million years. The Patagonian monster is reported as being very huge, so heavily armoured that a bullet could not penetrate to the vital organs, and as having made a great path through the forest. Some plesiosaurs were very large, though many were of moderate length, some being less than ten feet long, and none were covered with a bony dermal armour. The fore and hind limbs both constituted flippers or paddles similar to those of a whale and were not adapted for walking but were purely swimming organs. Most genera of the order Plesiosauria had long snake-like necks and small heads with sharp conical teeth suitable for catching living fish, which were probably their main diet Smooth pebbles, which it is thought were used to aid digestion, have been found in the stomach. The paddles were the main means of propulsion, the short tail probably serving as a rudder.
— CM. Sternberg.

Not a Plesiosaur. 1922 article in a Canadian magazine.

Onelli didn't believe it was a Plesiosaur

The Pathfinder, published in Washington DC, in its April 22, 1922 (No. 1477) has a lengthy article about the animal, it cites Onelli, is critical and considers it to be a yarn, tale, show. It does mention Onelli as stating that the creature is not a reptile, but an edentate (megafaunal animal) that survived extinction in the past 10,000 years. This of course was far more feasible than a surviving reptile from the Cretaceous. Below is an image from the article which you can read online.

" Prof. Onelli believes that if one such animal exists there must be two or more. He comments that “Martin Shetfield, who wrote that he saw the animal in a lake in the Esquel region, is my friend and is trustworthy. He is not a scientist, but I have not the least doubt that he saw a large and strange aniamal with a swan-like neck swimming the lake as he asserts. Sheffield is American who has been prospecting and hunting in that region for years. I have received a report that a similar beast was seen in 1913 by an Emglishman in a lake in Santa Cruz further south. These reports tend to confirm the previous rumors of the existence in Patagonia and other unexplored places: of animals unknown to moderns. Plesiosaurus is a pseudonym the newspers have given it,” he corrects. “! believe it is a huge animal of the edentate family, of which ancient remain -not fossils— were found in Patagonia 1897, and one of which was fired upon and hit by the explorer Ramon Lista in 1890 without hurting it. He says that from 1890 to the present time there ha been 12 places in Patagonia alone, between latitudes 38 and 52, where the mysterious creature has been reported alive and well.”
Prof. Onelli thinks they constitute a few surviving descendants of the armored glyptodon or the megatherium that lived in the pleistocene period. If you can imagine a creature resembling the armadillo, with strong limbs an short, broad feet and of the size of an ox you have some idea of the glyptodon, while the megatherium was a more or less gigantic toothless sloth about 20 feet in length which, with its short neck, heavy body and powerful tail, lumbered over the landscape, and with its strong prehensile tongue tore away leaves and twigs for food."

So, to be fair, it seems that the media named the animal a "plesiosaur" while Onelli insisted that it was an surviving megafaunal creature, in line with the Mylodon of 1898-1901.

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-202 5by Austin Whittall ©