288 - REVIEWS 
So also the Jurassic is recognized with doubt in the Navajo, Toldito, 
and Wingate sandstones of from four hundred to fifteen hundred feet in 
total thickness. Doubtless they include the equivalent of the Baptano- 
don beds of Wyoming, which in the southern part of that state are also 
represented by massive sandstones. But just how much of these sand- 
stones will prove to be of Jurassic age is doubtful. The McElmo, which 
farther east may be represented by dark-colored shales, is also doubt- 
fully located in the Jurassic. It probably includes the equivalent of the 
Morrison beds, which from the north to the south become progressively 
more sandstone, and should, the writer thinks, be included in the 
Comanche or Lower Cretaceous. 
The more precise correlation of the Mesaverde and Mancos beds 
with the Colorado and Montana groups of the Cretaceous ought not to 
be a matter of difficulty. The writer, from his observations in the 
Gallina Mountain region, just east of the San Juan Wasatch beds, 
believes that he identified both the Benton and Niobrara from charac- 
teristic fossils. It is much to be desired that local geological names 
should be abandoned wherever possible. For instance, the Eagle Ford 
and Austin shales of Texas are positively and precisely correlated with 
the Benton and Niobrara of Kansas by their vertebrate fossils, and 
their names should be abandoned. — 
The limited outcrops of Tertiary rocks in the Chuska Mountains and 
farther to the southwest are referred with doubt to the Eocene, because 
of the absence of fossils. 
Altogether Professor Gregory’s work in these fields will serve as an 
excellent guide to the future explorer. Much remains to be done in the 
more precise correlation of the strata; and the prospects for the verte- 
brate paleontologist, at least, are full of encouragement; he has been 
groping hitherto. ; 
5. W. W. 
