284 



University of California Publications in Geology 



[Vol. 12 



The drawings** were made, with great care, by Miss Frieda Leud- 

 demann under the personal supervision of the writer. 



The writer would acknowledge the many kindnesses and good will 

 of the owners of the properties where the explorations have taken 

 place, especially Mr. Blackburn, of Hemet, the proprietor of Eden, 

 Mr. Weaver, and many others. He further wishes to draw attention 

 to the enthusiastic cooperation of his field assistant, Mr. Joseph Rak, 

 to whose keen interest and long training as miner and prospector the 

 success in the field was largely due. 



HISTORICAL 



Palaeontologically up to the time of the present investigation the 

 two regions were virgin territory and unmentioned in the literature. 

 Geologically the San Timoteo Badlands had been interestingly dis- 

 cussed by Dr. AV. C. MendenhalF in his study of the water supply 

 of the San Bernardino Valley, in which he points to their great 

 economic importance in forming the impervious southern wall of a 

 natural supply basin. While no vertebrate fossils had been reported 

 from the San Timoteo area at the time of writing, nor previous to the 

 present work, an interesting specimen had been returned from the 

 Bautista deposit. This, the posterior portion of the mandible of a fossil 

 horse containing Pj and Mg, had been unearthed in the fall of 1916, by 

 ]\Ir. Blackburn, on his fruit ranch, Bautista Creek, Hemet, and sent 

 to the University of California. At the University it had come into 

 the possession of Professor John C. Merriam and had suggested the 

 desirability of an exploration of the neighborhood. At the midwinter 

 meeting of the Pacific Coast section of the Paleontological Society 

 held in April, 1917, the writer read a short report on the work he 

 was then cai-rying on in this Bautista deposit. 



6 The sketches were first laid off according to the greatest transverse and 

 anteroposterior measurements; and in the case of shaded drawings these measure- 

 ments were used as the basis on which to make the slight necessary foreshorten- 

 ing. In the case of the sketches of the occlusal views of the horse teeth all were 

 drawn in the actual plane of the triturating surfaces. The tooth measurements 

 given in the schedules, on the other hand, were taken perpendicular to the tooth 

 axis, and always exclusive of the cement. The anteroposterior diameter is the 

 greatest distance between the anterior and posterior tooth facets in both the 

 upper and the lower teeth. The transverse diameter of the upper equine teeth is 

 the greatest distance between the outer extent of the mesostyle and the inner wall 

 of the protocone ; the transverse diameter of the lower teeth is the greatest distance 

 between the inner extent of the metastylid and the outer wall of the protoconid. 



Hydrology of San Bernardino Valley, California. U. S. Geol. Surv., Water 

 Supply Paper no. 142, 1905. 



