Discovery of a new bed of ancient fossils in southern Brazil has proved a great step forward for the expedition of Llewellyn I. Price and Theodore E. White of the Museum of Comparative Zoology.

After over a year of exploration of in the State of Rio Grande do Sul, six months of which were too rainy to allow digging, the men located the 175,000,000 year old fossil bed in the red clay footbills of the Brazilian Platean. It is believed to be the most significant American deposit yet found of the fauna of the Triassic period, critical in the development of the ancestors of the dinosaurs and mamals.

African Comparison Possible

As a consequence of this find paleontologists will be able to make their first detailed comparison of Triassic forms in this hemisphere with those in South Africa, where many deposits from this period abound. After preliminary study the experts have found similarities between the two, confirming other evidence of early transcontinental migrations.

New Finds

Price and White have just returned from the field and have brought with them remains which constitute the finest cross-section of South American Triassic life ever made available for scientific study. Of the 30 nearly complete skeletons at least 15 are entirely new to science. About five years of museum work will be necessary to analyze these bones.

History Of Era

In scrutinizing the Permian, and the immediately following Triassic, periods, the Harvard Paleontologists are dealing with the origins of the Mesozoic era, or the 100,000,000-year "reign" of the great reptiles. Developed from hardier amphibans, the Permian and Triassic reptiles were the first forms of life able to live and to rear their young outside the water. For millions of years the descendants of these pioneer land forms ruled the earth, taking final form in some cases as the giant dinosaurs. Then the reptile domain abruptly ended, and when the fossil story resumes, after a long lapse, it is the mammals who are dominant, while only a half-dozen reptile groups remain.

Just west of the little town of St. Cruz, the scientists found the natives had burned extensive quantities of rock, making plaster. In this red clay territory, they explained where there are rocks there is a good chance of finding fossils. Thus the local kilns served as rough land marks, guiding the scientists to their major finds.

This native plaster industry which has been in operation for sixty years, has presumably destroyed untold quantities of Triassic fossils. The specimen from the new chasmatosaurid genus was rescued from a rock pile destined for one of the kilns.

Mammal-Reptile Link

The Harvard Paleontologists were on an especial lookout for any traces of mammal-like reptile fossils. The origin and development of the mammal class is one of the most significant features of Mesozoic evolution. The cold-blooded ancestors of man and the other animals, who were somehow equipped to survive the conditions that eliminated most of their follow reptiles, have left relatively little evidence of their progress during these hundrd million years.

EARLY OFF SHOOTS

From the early and relatively short-lived off-shoots of the main mammalian trunk, the Harvard Paleontologists assembled many specimens. Of the family of cynodonts,--small, dog-sized, carnivorus lizards,--they obtained the finest fossils ever found in the Americas. The collection includes a large number of complete cynodont skeletons and skulls in good preservation. The world's chief cynodont deposits are in South Africa, and hitherto only fragmentary skulls of this family have been found in South America.

Herbivorous Two-Tusker

Of another mammal-like family, the herbivorous "two-tusker," or dicynodont, the Harvard party obtained a number of good skulls and skeletons. These peaceful lizards, six feet or so in length, were among the commonest reptiles in the Triassic period, but were rapidly killed off, probably by their meat-eating cynodont relatives and other carnivorous forms.

The cynodonts and dicynodonts are important for evolutionary study, since these families show already early signs of the evolutionary development that led from the lizard-like animal to the true mammal, which dominates the world today.

Many of the fossils brought back from Brazil are of genera never before seen by man. One of these, a delicately boned lizard, about fifteen inches long, belongs to the order of thecodonts, whose evolution developed some of the greatest dinosaures. Another specimen, an oddly crushed reptile skull, is believed to be chasmatosaurid, belonging to a carnivorous alligator type, probably about twelve feet long. Other new animals were found in the cynodont, dicynodont, and rhynchosaur groups.