722 A CENTURY OF PROGRESS IN THE NATURAL SCIENCES 



region in great detail. He proposed the name Vindelic Chain for a former moun- 

 tain range north of the present Alps, extending from north Bavaria westward to 

 the plateau of central France, and accounted in this way for the differences in 

 lithology of the Alpine and Extra-Alpine Triassic. 



The investigations of E. von Mojsisovics in Austria between 1866 and 1896 

 emphasized the paleontologic basis for the classification of the Triassic massive 

 limestones in contrast to the earlier divisions founded on lithology. The Triassic 

 rocks of the Himalayas and Salt Ranges of India were studied by von Mojsiso- 

 vics, Diener, and Waagen under the auspices of the Geological Survey of India 

 and have been classified largely on the basis of the divisions established in the 

 Alps. An evaluation of the Permo-Triassic horizons, including that containing 

 the Djulfa fauna in Armenia, has been described by A. Stoyanow. L. F. Spath, 

 in his monograph on the Ammonoidea of the Trias in 1934, has also contributed 

 greatly to the discussion of these problems. 



The Triassic rocks of eastern North America, extending from Nova Scotia 

 into South Carolina, consist of continental red beds corresponding to the Keuper 

 series of Germany and were named the Newark series. These sediments, ranging 

 from 10,000 to 20,000 feet thick, along with basic lavas, accumulated in down- 

 faulted troughs and were derived from the erosion of the recently uplifted Ap- 

 palachian Mountains. 



The Triassic continental beds of the Cordilleran basins of western North 

 America were studied for nearly one hundred years hy the United States ex- 

 ploring expeditions and later by the U. S. Geological Survey. They consist of 

 colored shales, sands, and conglomerates, which have been named the Moenkopi, 

 Shinarump, and Chinle formations. Marine members interfinger with the Moen- 

 kopi formation toward the west and in California and Nevada attain thicknesses 

 as great as 20,000 feet. These deposits contain rich ammonite faunas, which were 

 described by J. P. Smith and Alpheus Hyatt in 1905 and by J. P. Smith in 1927. 

 The relation of these faunas to those of the Himalayas and Alps made possible 

 an interpretation of seaway connections which during the Lower Triassic con- 

 nected the Great Basin sea with the Arctic to the north and also with Tethys 

 Basin, as pointed out by Smith. Later the connections were thought to be with 

 the Mediterranean through the Central American portal and a mid-Atlantic 

 archipelago. Again this avenue was closed and a Pacific boreal passage opened. 

 The Upper Triassic faunas of western North America indicate that the connec- 

 tion was once more with the Mediterranean except at the end of the period when 

 boreal faunas again came down from the Arctic. 



Jurassic: The contributions of William Smith, together with those of Cony- 

 beare and Phillips, made the Jurassic succession in England well known by the 

 middle of the past century. It was classified as the Lias and tlie Ijower, Middle, 

 and Upper Oolite. The early work of Humboldt, Brongniart, Merian, Thur- 

 mann, Dufrenoy, and Elie de Beaumont outlined the general features of the 

 Jurassic rocks of Switzerland, France, and south Germany. Those of south Ger- 

 many were divided into Black, Brown, and White Jura by von Buch, who laid 

 the foundations for the important contributions of F. A. Quenstedt. In these the 

 three main groups were each subdivided into six subgroups and an important 

 section was established in the Schwabian Alps which was extensively used as a 

 standard for correlation. 



