120 TJie America7i Geologist. August, 1892 
Bertragc zur Geologic, and Paleontologie der Republik Mexico; von Dr. 
J. Felix und Dr. H. Lenke, (of Leipsig). Part i, Leipsig 1890. Part 
III, Stuttgart 1891, 4to, with numerous plates and maps. 
This work is the most important contribution to the geology of Mex- 
ico yet published, and by its excellent character and scientific composi- 
tion immediately assures the reader of the ability and intelligence of 
its authors. Space forbids, however, the enumeration of all the valua- 
ble contents, which shed so much light upon North American geology. 
Part I, after a preface explanatory of the lack of previous knowledge 
of Mexico, and an introductory sketch of its salient features, is devoted 
to the "volcanic chain of central Mexico, including descriptions of 
Tuxtla, Popocatapetl, Ajisco, Nevada de Toluca, Jorulla, the peak of 
Tancitaro, Colima, Orizaba, Cofre de Perote, Malinche, Iztaccihuatl, San 
Andreas Ceboruco and Tepie. It is impossible to enumerate here the 
numerous and important results given, but every line is a much desired 
contribution to knowledge, especially that concerning the glaciers of 
Popocatapetl. 
Part II is devoted to the valley of Mexico, and of itself is one of the 
most important contributions to the late Tertiary Geology of this conti- 
nent. Several pages are devoted to a careful topographic sketch full of 
important data. Chapter 2 describes the remarkable Pleistocene de- 
posits, showing a striking resemblance to the features of our own lake 
Bonneville as described by Gilbert. The earlier discoveries of a 
Pliocene vertebrate fauna by Cope are supplemented by new data. This 
fauna, consisting of Equus, Elephas, Mastodon Glyptodon, Bison, etc., is 
similar to that of the Fayette beds of Texas and the Equus beds of the 
great basin region. 
The eruptive rocks of the valley were studied by Zirkel, and consist 
of amphibole andesites, hypersthene andesites of many kinds, and 
basalts. Finally a full table of altitudes is given. 
Part II contains two papers, the first by Drs. Felix and Lenke on the 
Geology of the State of Puebla, and the second by Dr. Felix on the Fos- 
sils of the Jurassic and Cretaceous formations of Mexico. In the part 
on Puebla the general geology is shown to consist of Cretaceous and 
Jurassic limestones, and the Pliocene Equus beds. Full notes are given 
on the fossil vertebrates of the latter formation. The Cretaceous is 
shown to consist of an upper horizon of limestones with Hippurites 
and Monopleura, which we believe analogous to the Monopleura and 
Caprina beds of the Glen Rose limestones of the Comanche series in 
Texas, while the lower division is very analogous to the Trinity forma- 
tion of the same region. The remarkable superficial formation known 
in Mexico as tepetate is described— an incrustation of carbonate of lime 
deposited over the valleys ly the streams from the limestone mountains. 
The second part of Part 11 contains accurate descriptions and beauti- 
ful plates of the Neocomian and Jurassic fossils of Puebla. If any one 
still doubts the existence of the marine Jura in North America an ex- 
amination of these plates should convince him of his error. 
