Reviews—North American Paleontology. 377 
selbyensis (Miocene);  Sprsula acutirostrata, S. merriamt, and 
S. tejonensis (Kocene); and Spisula chicoensis (Cretaceous). A distri- 
bution table, both geological and geographical, adds to the importance 
of this work, the species ranging from Cretaceous to recent times. 
The Miocene is referred to as ‘‘ the period of the greatest generic and 
specific differentiation of the family’, the older forms being fewer 
and relatively constant in shape. The author’s able explanations of 
the taxonomy and phylogeny of this group of shells are rendered 
still more interesting by the excellent plate-illustrations which adorn 
the memoir. 
R. BLN, 
AV.—SrratickaPHy AND Fauna oF THE Tryon Eocene or CaLirornia. 
By Roy E. Dickerson. Univ. California Publ. Bull. Dept. Geol., 
vol. ix, No. 17, pp. 363-524, pls. xxxvi—xlvi (chiefly Mollusca 
and views of localities) and text-illustrations (maps, sections, 
ete.),. 1916. 
‘Y\HE author recognizes four faunal zones in the Tejon Group of 
California, which, in ascending order, are named the Zurbinolia 
zone, the Rimella simplex zone, the Balanophyllia variabilis zone, and 
the Siphonaha sutterensis zone. Stratigraphical and faunistic details 
are given of these zones, maps of California being also introduced 
showing the probable extent of the Tejon sea during the deposition 
of the rocks containing the different zonal faunas. This Eocene fauna 
is said to embrace about 300 species, 25 of which range downward 
into the underlying Martinez Eocene, while 3 or 4 occur in the 
Oligocene beds above. ‘The species are fully listed from the various 
localities of the region, while some 15 Pelecypoda and about 30 
Gastropoda are described and figured as new species. As geological 
investigators rarely attempt zonal work on the Tertiary formations, 
‘the author deserves our congratulations on his discovery of well- 
defined zones in this group of rocks, which adds an interest and 
a greater accuracy to our previous knowledge of these deposits. 
Teed a Se 
V.—Fauna Srupies 1n THE Cretaceous oF THE Sanra Ana Movn- 
TAINS OF SourHERN CaLirornia. By Hart Leroy Packarp. Univ. 
California Publ. Bull. Dept. Geol., vol. ix, No. 12, pp. 187-59, 
with 1 map, 1916, 
lie carrying out his researches on the Cretaceous faunas of the 
Santa Ana Mountains, the author recognizes relationships to 
those characterizing other Cretaceous regions of California, especially 
with the Chico fauna of Shasta and l'ehama Counties, to that of the 
underlying Horsetown Series. Foreign affinities of the faunas are 
more difficult to trace, although it is stated that, according to F. M. 
Anderson, they favour the Turonian of Europe as well as resembling 
the life groups as found in the Cretaceous deposits of Southern India. 
