122 The American Geologist. February, is;.? 
is the reference of the Chico-Tejon formation of ('alifornia to 
the Cretaceous system, instead of putting it at its right place, 
the Tertiary Eocene. 
Dr. A. Randall first discovered at Chico creek, Butte coun- 
ty, California, in 1855, a series of strata containing a rather 
rich fauna, composed mainly of gasteropods and acephales, 
essentially characteristic of the Tertiary Eocene. Dr. Trask, 
the first geologist appointed by the State of California, on the 
recommendation of Dr. Randall, made a careful study of the 
locality, in following the clitfs of the Chico creek, which are 
rather difficult to explore on account of a flow of lava vol- 
canic rocks, which covers the Tertiary strata. Among the 
numerous Tertiary fossils two cephalopods were found, the 
Baculites chicoensis and Ammonites cJiicoevsis, two degenerate 
forms, according to the best authority on cephalopods, pro- 
fessor A. Hyatt. Both Drs. Randall and Trask had no hesi- 
tation in referring the strata of Chico creek, according to the 
principles for correlation established by Alexandre Brong- 
niart, to the Tertiary; and Dr. Trask published those two 
cephalopods in "Description of a new species of Ammonites 
and of Baculites from the Tertiary rocks of Chico creek"( Pro- 
ceed?. California Acad. Nat. Soc, vol. i, p. 85, San Francisco). 
In classifying the T'hico series as Eocene Tertiary the authors 
followed the rules for establishing synchronism and equiva- 
lency at great distance from the typical region of the recog- 
nized great systems or geological epochs. M. A. Remond de 
Corbineau, an excellent expert for Cretaceous and Tertiary 
rocks, after an exploration of Monte Diablo referred also, in 
a Beport of Monte Diablo district, the same series of rocks to 
the Eocene Tertiary or Chico creek group of Drs. Randall and 
Trask. 
But the correlation was not accepted by the group of the 
leaders of American geology, who declared that it was impos- 
sible that Ammonites and Baculites existed in California dur- 
ing the Eocene time, when such invertebrate marine animals 
did not exist in Europe, or even on the Atlantic borders of 
North America. Against all kruiwledge of geographic distri- 
bution of marine animals of the present time some palaeon- 
tologists have established the mathematical rule, that forms of 
animals have disappeared all over the surface of the terres- 
