DEVONIAN. 271 



H-I 12. SOUTHEBN ARIZONA AND NORTHERN SONORA. 



The sections at Globe and Bisbee, described by Ransome/"*-'*'^ include limestone 

 which contains late Middle or Upper Devonian fossUs. At Globe the formation is 

 continuous upward with' Carboniferous (Mississippian) limestone, as are the Ouray 

 limestone of, Colorado and the limestones described by Dumble.^^^ 



At Bisbee the Martin limestone (Devonian), 340 feet thick in the tj^pe section, is 

 distinguished from the Abrigo limestone (Cambrian) below and the Escabrosa lime- 

 stone (Mississippian) above it. The fauna is described and correlated by Williams, '^^^ 

 who concludes that its affinities are with the Neo-Devonian of New York but that in 

 Meso-Devonian time the fauna occupied the Arizona province in migration from 

 Russia. 



Williams comments on the fauna as follows : 



The species Atrypa reticularis is present in 25 of the 30 faunules. Some one or more of 

 the corals are found in 11 of the faunules. [Six of] the faunules * * * contain several 

 species of the reef-building corals and probably represent a common fauna. 



Associated with these corals are species " which indicate distinctly the fauna so well devel- 

 oped in the Devonian rocks at Rockford, Iowa. On the supposition that Spirifer hungerfordi and 

 Spirifer whitneyi are characteristic species of that fauna, the following species, associated with 

 them ia the Bisbee quadrangle, are now added to it — that is, Dielasma calvini, Productella 

 speciosa, Spirifer cf. jeremejevi. These twelve species, at least, are therefore probably present 

 in a common fauna of this Arizona region, which is also represented in Iowa, and is certainly of 

 Devonian age. 



Its comparison with New York and northern Appalachian faunas indicates close affinity 

 with a fauna occurring at the base of the Chemung formation of New York, above the typical 

 Ithaca formation. In the High Point zone of Naples, Livingston County, N. Y., the species 

 of the genus Strophonella reported is S. reversa. The fofm reported in the above list is S. 

 cxlata, which occurs in the Stropheodonta cayuta fauna of the southern counties of New York 

 and across the border in Tioga and Bradford counties, Pa., but not, so far as I have observed, 

 in the High Point fauna. In this southern extension it is associated with typical Spirifer 

 disjunctus. The Productella of the Arizona region is also of the same type as that represented 

 in this upper (Chemung) zone rather than in the underlying typical Ithaca zone of Productella 

 speciosa. The evidence is therefore confirmatory of the opinion that this western American 

 fauna did not reach the upper Appalachian region, in its full complement, until after the depo- 

 sition of the zone oi the Ithaca formation. 



It is to be observed, however, that in Russia the fauna with which this Arizona fauna shows 

 closest affinity is classed by Tschernyschew as middle Devonian rather than upper Devonian and 

 occurs below the Cuboides fauna. It is also regarded by him as equivalent to. the Stringocephalus 

 fauna, which in western Europe is strictly Mesodevonic. This is further correlated by Tscherny- 

 schew with the Hamilton group of North America. 



********* 



There can be little doubt as to the close affinity of the Arizona and Russian faunas 

 here referred to. Comparison of Spirifer hungerfordi, as it occiu^ both in Iowa and Arizona, 

 with Russian specimens of Spirifer anossofi demonstrates the two to be closely related, as 

 Tschernyschew maintained; but the rounded cardinal angle as well as coarser radiating striae 

 mark the figures of S. anossofi of Tschernyschew (as well as actual specimens seen by me), 

 from the Sp. hungerfordi as it is seen both in Iowa and Arizona. There are figures in the original 



"For list see the work cited. — B. W. 



