112 D. E. SAVAGE 



the Cretaceous, the first and principal sign of the richly fossiliferous 

 matrix was an accumulation on an ant hill of tiny teeth, gar scales, 

 reptile teeth, and the like. 



These are admittedly the words of an enthusiast. Screen washing 

 is not the solution for all collecting problems, and it is efhcient only 

 as a mass production technique. Some matrices and some fossils are 

 not susceptible to this type of treatment. But the method is useful 

 in many areas, and it may be especially useful for census and ecology 

 studies in the varicolored flood-plain formations that have been pro- 

 claimed barren by previous workers. 



The possible contrast in abundance of adaptive types between 

 samples from the drab gray quarry pockets and the varicolored 

 flood-plain deposits is also interesting. In the continental late Paleo- 

 ceneof the Rocky Mountains, Simpson (1935, 1937) and Van Houten 

 (1945) found that the small herbivores abound in the quarry samples 

 and that the large herbivores, carnivores, and carnivore-omnivores 

 are relatively abundant in the scattered surface finds. Combined 

 floral, faunal, and sedimentological data show that these late Paleo- 

 cene environments were in intermontane lowlands and were subject 

 to humid warm-temperate or subtropical climate (Knowlton, 1917, 

 1924; Berry, 1935; Bell, 1949). By contrast, work in the late Mio- 

 cene deposits in the Cuyama Badlands of southwestern California 

 shows quite difi"erent proportions of adaptive types. Figure 5 gives 

 the stratigraphic correlation between red-bed and gray-bed occur- 

 rences of land mammals within the Caliente formation in this area. 

 Present mapping and studies of the physical stratigraphy of the 

 district indicate that the red-bed and gray-bed mammal locations, 

 here assigned to the Barstovian (late Miocene) Mammalian Age, 

 are geochronologically contemporaneous. Figure 6, a preliminary 

 census of the Caliente formation mammals, is based on both surface 

 collecting and incomplete quarrying in both lithofacies. In this com- 

 parison it may be noted that the small insectivores and herbivores 

 (including rodents and rabbits) are relatively abundant in the red 

 beds, whereas large herbivores, such as camels, horses, and oreo- 

 donts, are the dominant element in the gray-bed faunule. The 

 Cuyama example, therefore, suggests a quite different relationship 

 between lithofacies and mammalian adaptive types. Combined 

 paleontological and geological evidence shows that the Cuyama 

 paleobiotope was in coastal intermontane valleys and was subject 



