HOMOTAXIS OF THE FAUNA. 409 



General Remarks. — The discovery of the parallelism between the faunas 

 of the Jura in India by Waagen, in Australasia by Moore and Etheridge, 

 and in South America by Bayle and Coquand, Marcou, Gottsche, Stein- 

 mann, and the author of this paper, makes one more confident in de- 

 ciphering the somewhat fragmentary remains found in these rocks, since 

 everywhere homotaxial relations have been found to exist and it has 

 been discovered that there is plainly parallelism in the evolution of the 

 faunas on the different continents, enabling one to make close compari- 

 sons between the different series and often also even between the sul (di- 

 visions or stages of those series, as has been done provisionally in this 

 paper. 



So far as the paleontologic researches have extended, they show that a 

 series of fossil faunas exist in the rocks of Mount .Jura, which approxi- 

 mately represent the three great subdivisions of the Jura, namely, the 

 lower, middle and .upper Jura ; and these in their general faunal char- 

 acters and associations of forms are, considering their wide removal from 

 the European localities, not more distinct than one might very reasonably 

 have anticipated. 



All explorations have hitherto failed in bringing to light any very re- 

 markable or entirely new types, such as have been found among the 

 vertebrata on this continent. The general scarcity of the remains of 

 vertebrates at Taylorville is another notable feature. A few fragments 

 have been found, and possibly diligent and prolonged special research 

 might bring to light more specimens and species, but they are not com- 

 mon, since the explorations, although confined to the surface, were 

 thorough. Tins fact is applicable to the entire column of the Trias and 

 •Jura as heretofore explored along the western slopes of the Sierras and 

 Andes, and it is probable that these faunas lived at some distance from 

 the shores of the Jurassic continent and in a more open oceanic area 

 than those of the Rocky mountain region or Europe, a conclusion in 

 complete accord with the results of geologic research. In making com- 

 parisons between the Jura of Taylorville and that of Aurora, Wyoming, 

 near Red buttes on the North Platte, and of the Black hills,* one is 

 struck first by the fact that the latter were deposited in the same basin, 

 the species being largely identical, as already demonstrated by Meek; 

 and then, thai they can lie spoken of together as having the distinctive 

 characteristics,)!' the fauna of (he Calloyian or ( ).\ fordian in the upper 



♦ Localities near N irthside, Bull Lake fork, southeastern [daho, and on Aquarius plateau, I I ill 



have fossils apparently of the at 'fauna; but so little has 1 a collected that one cannol sp< 



wiili certainty. Campionectet and < >.-h ,i ,<, found al various localities in Utah an. I descril ed bj I 'i . 

 White in the report on Explorations west ol the 1 00th Meridian (vol, iv, pari t) indicate the presence 

 of similar frag ni-' of the Callovian or Oxfordian ai other localities in Utah. 



