714 JAMES H. GARDNER 



tion of the group to the two formations here discussed is shown as 



follows : 



iTorrejon formation 

 Unconformity (?) 

 Puerco formation 



This name is taken from the town by that name in the type-locality 

 at the foot of the Nacimiento Mountains. Here Cope mentions the 

 importance of the "Puerco," which he used to include everything 

 between the "Laramie" and the Wasatch in this region. 



GEOLOGY OF THE TYPE-LOCALITY 



The following observations and conclusions, together with the 

 map, are based on the writer's field work in the summer of 

 1907 under the supervision of Mr. M. R. Campbell. In the prepa- 

 ration of the map and securing of geologic notes, valuable assistance 

 was received from Mr. William J. Reed (deceased) and Mr. Albert 

 L. Beekly. 



The results of this work were chiefly of value in that a map was 

 prepared of the region westward from the Sierra Nacimiento and on 

 this the geology was imposed. The unconformable relationship of 

 the Nacimiento group was noted for the first time and something 

 was learned of the physiographic record of the district in the late 

 Cretaceous and early Tertiary. Unfortunately, the advantage was 

 not at hand of having paleontologic determinations in the field in 

 order to know what formations were being dealt with at that time. 

 For instance, no distinction could be made in the lithologic character 

 of the upper and lower beds of the Nacimiento group, the result being 

 that the Puerco and Torrejon formations were not mapped separately. 

 At the time of the field work, the writer had not had occasion to be 

 famihar with the literature on the Puerco, Torrejon, and Wasatch 

 of this field, and did not know the stratigraphic position at which 

 fossil vertebrates had previously been found. The results in paleon- 

 tologic collecting were, however, all that could be expected under the 

 circumstances and were sufficient to make possible definite correlations. 



The region under discu'ssion is one of little culture and sparse 

 population. Galhna is a small Mexican settlement of about 100 

 people, located at the point where Gallina River emerges from the 

 Sierra Nacimiento. About 14^ miles south-southwest is the old 



