CLIMATES OF GEOLOGIC TIME—SCHUCHERT. 297 
Our knowledge of the land vertebrates of late Paleozoic time is 
increasing rapidly, and it is becoming plainer that great changes were 
also in progress here. The vertebrates of the Coal Measures, either 
the armored amphibians (Stegocephalia) or the primitive reptiles, 
were still largely addicted to the ‘‘water habit” and lived in fresh 
waters or swamps, but this was much changed by the arid climates 
and vanishing swamps of later Permic times, and in the Triassic we 
meet with the first truly terrestrial reptilian faunas. 
A climatic change naturally must affect the land life more quickly 
and profoundly than that of the marine waters, for the oceanic areas 
have stored in themselves a vast amount of warmth that is carried 
everywhere by the currents. The temperature of the ocean is more 
or less altered by the changes of climate, be they of latitude or of 
glaciation. The surface temperatures in the temperate and tropical 
regions, however, are the last to be affected, and only change when 
all of the oceanic deeps have been filled with the smking cold waters 
brought there by the currents flowing from the glaciated area. We 
therefore find that the marine life of earlier Permic time was very 
much like that of the Coal Measures, and that it was not profoundly 
altered even in the temperate zones of Middle Permic time (Zechstein 
and Salt Range faunas). Our knowledge of Upper Permic marine 
life is as yet very limited and will probably always remain so because 
of the world-wide subtraction of the seas from the lands at that time. 
It was a period of continued arid climates, and the marginal shallow 
sea pans were, as a rule, depositing red formations with gypsum, and 
locally, as in northern Germany, alternations of salt with anhydrite 
or polyhalite in thicknesses up to 3,395 feet. In certain of these 
zones there were developed annual rings so regular in sequence 
as to lead to the inference that they were the depositions of 
warm summers and cold winters, enduring for at least 5,653 years. 
(Gérgey, 1911.) 
Triassic.—When we examine into the Triassic faunas we meet at 
once with a wholly new marine assemblage. The late Paleozoic 
world of fusulinids, tetracorals, crinids, brachiopods, nautilids, and 
trilobites had either vanished or was represented by a few small and 
rare forms. On the other side, in the Triassic, their places were 
taken by a rising marine world of small invertebrates, now hexacorals, 
regular echinids, modern bivalves (among them the oysters), siphonate 
gastropods, and more especially by a host of ammonites and a 
prophecy of the coming of squids and marine reptiles. Truly, there 
is no greater change recorded in all historical geology. | 
Plants are scarce in the rocks of Triassic time until near its close 
in the Rhetic, when we can again truly speak of Triassic floras. 
These are known from many parts of the world, and according to 
Knowlton there is nothing in the floras to suggest a “depauperate 
