Ceagin.] LOCALITIES OF RELATED FAUNAS. 21 
The number of fossils known from the Jurassic of the Cerro de 
Titania is small, but indicates, so far as it goes, a position high in 
the upper Jurassic series, as shown by Doctor Felix ; and it is at 
least worthy of note that of the few lamellibranchs known from 
these rocks, Exogyra subplicifera and Gryphoea mexicana occur 
also at Malone, Astarte microphyes may be the same as A. brexiacola, 
and the large Trigonia sologureni, known only from the cast, may yet 
prove to be identical with the Malone species, T. vyschetzkii, when the 
details of its shell come to light. 
Besides the Malone district, the Sierra de Catorce, and the Cerro 
de Titania, several other localities in Mexico have yielded fossils of 
the Malone formation. Thus a Perisphinctes, supposed to be related 
to the European P. balderus, is apparently common to the Theta'and 
the Alamitos and is reported from Tutotepec also, in the State of 
Puebla, by Castillo and Aguilera ; and by the same writers Peri- 
sphinctes mazapilensis and Haploceras mazapilensis are recorded 
from the Alamitos and from the Sierra de Zuloaga, in Zacatecas. 
A number of Mexican Jurassic localities besides those here men- 
tioned are given in Aguilera's " Sinopsis de Geologia Mexicana; " a 
but these are little known, and at some of them the rocks belong, at 
least in part, to the lower Jurassic. It is, however, interesting to 
note that the Jurassic district of Malone is in the continuation of the 
belt along which are scattered all or nearly all of the Jurassic tracts 
shown on the geological map of Mexico of 1897 published with Nos. 
4-6 of the Boletin del Instituto Geologico de Mexico. 
It is not improbable that rocks nearly related to the Malone occur 
in South America. As shown in the discussion of that species, 
Trigonia cyschetzkii is very close to the Andean form, T. transitoria 
Steinmann, a species whose precise geological position has hitherto 
been doubtful, but which the evidence from the Malone district tends 
to show probably belongs to the upper Jurassic. 
ACKNOWLEDGMENTS. 
I wish to acknowledge my indebtedness to all of those mentioned 
elsewhere herein as having contributed directly or indirectly to the 
success of this study. The kind services of the Messrs. Goodell were 
of especial value, as furnishing the first fairly conclusive indication 
of the Jurassic age of the Malone formation. To the Hon. Charles 
D. Walcott, Director of the United States Geological Survey, and 
to Mr. Charles Schuchert, Curator of Invertebrate Paleontology in 
the United States National Museum, I am indebted for important 
aid. I am under obligations also to Mr. John N. Gilcrease, Mr. 
a In Bosquejo, Geologia de Mexico : Boletin del Instituto Geologico de Mexico, Nos. 
4-G, pp. 187-250. 
