644 



SCIENCE 



[N. S. Vol. XL. No. 1035 



under the leadership of Dr. Bruce Clark, in- 

 structor in paleontology, obtained an interest- 

 ing collection of remains of land mammals in 

 Tertiary deposits north of Ooalinga, on the 

 west side of the Great Valley of California. 

 As the Tertiary section in the Coaling-a region 

 is a part of the marginal marine series of 

 Californian formations, and the mammalian 

 remains obtained in these beds represent a 

 land fauna best known in the epicontinental 

 deposits ranging from the Great Basin east 

 to the Great Plains region, this occurrence 

 offers an unusual opportunity for correlation 

 between the marginal marine province and the 

 mammal-hearing deposits of the interior of 

 the continent. 



Evidence bearing on the problem of corre- 

 lation between the Great Basin and the 

 Pacific Coast province is particularly welcome 

 at this time, since there has been reason to 

 believe that the geologic scales used in the 

 two regions have not coincided in the limits 

 of the periods. 



The mammalian remains obtained in the 

 North Coalinga region were found at not less 

 than four horizons ranging from beds gen- 

 erally considered to be Lower Miocene or 

 Upper Oligocene, to a horizon of Pleistocene 

 or Pliocene stage. The occurrence of the 

 f aunal zones in the sequence of deposits in the 

 North Coalinga region is shown in the table. 



The lowest horizon is characterized by 

 abundance of horse teeth representing the 

 genus MerychippuSj and may be known as the 

 Meryehippus zone. At the second horizon 

 from the base comparatively few remains are 

 known. The presence of teeth of Neohipparion 

 suggests the tentative designation of this por- 

 tion of the section as the Neohipparion zone. 

 The third of the principal horizons is char- 

 acterized by the presence of a new species of 

 horse designated as Protolnppus coalingensis 

 and may be known as the Protohippus coalin- 

 gensis zone. The latest fauna is distinguished 

 by the presence of a large specialized horse, 

 probably representing the genus Bquus, and 

 by remains of a form near Cervus. This may 

 be known as the Equus-Cervus fauna. 



Occurrence of Mammal Zones in Tertiary Beds of 

 the North Coalinga Region of California 



The fauna of the Meryehippus zone occur- 

 ring in the " Temblor " beds commonly recog- 

 nized as Lower Miocene, includes the follow- 

 ing types. 



Meryehippus, n. sp. 



Tetrabelodon ?, sp. 



Procamelus ?, sp. 



Prosthennops ?, sp. 



Desmostylus, near hesperus Marsh. 



Isurus, sp. 

 The horses of the Meryehippus zone corres- 

 pond very closely in most respects to Mery- 

 ehippus isonesus of the Mascall Middle Mio- 

 cene of the eastern Oregon region. The stage 

 of evolution of the teeth of this form is not 

 reached by any species of the Lower Miocene 

 in America. The proboscidean, Tetrabelodon?, 

 has no certainly known relatives in America 

 earlier than the Middle Miocene of our ac- 

 cepted scale. The camel resembles a late Mio- 

 cene type. It seems impossible to refer this 

 fauna to a stage older than that of the Mas- 

 call Miocene of the mammalian sequence of 

 the Great Basin province. 



From the occurrence of the Meryehippus 



