Geological Nates on the sierra Nevada. — Turner. 23i> 
of fossil plants. The shells were determined by Dr. White and 
Mr. Stanton as belonging to Corbicula, a genus found only in 
fresh and braekish waters. The Corbicula bed overlies sand- 
stones containing abundant Chico fossils, and underlies the 
white shales and day of the lone formation that is capped by 
the basalt of the table mountain. It is possible that the Cor- 
bicula bed represents the Eocene period and perhaps the 
Puget group of Washington. 
Ocoya Creek Beds. 
Prof. W. P. Blake* reported extensive deposits of Miocene 
age in Tulare county on Ocoya or Pose creek and further 
south. 
The fossils collected by Blake were casts, and from these 
Mr. Conrad described a number of species. As there is a 
probability that all of these fossils cannot hereafter be recog- 
nized, only the following are given, these having been identified 
by Gabb from later collections : 
Agasoma gravida Gabb; undet. Conrad. 
Xatica recluziana Gabb; ocoyana Conrad. 
Pecten catilliformis Conrad. 
A considerable number of shark teeth were found and 
studied by Prof. Louis Agassiz. According to Prof. Whitney, 
the upper portion of the beds are of a later and fresh water 
origin and contain fragments of bone and wood. There is a 
possibility of correlating the lone formation with these beds. 
Ione Formation. 
This term was first used by Mr. W. Lindgren, in thedescrip- 
tive text of the Sacramento sheet, for the beds of clay and 
sand, with layers of lignite, that occur along the foothills of 
tlie Sierra Nevada and seem to have been deposited at the 
same time as the earlier auriferous river gravels, which are 
usually composed chiefly of white quartz pebbles. The series 
is best developed in Amador and Calaveras counties, where 
the writer has been aide to separate it into three portions, as 
follows, in descending order : 
lone formal ion. 
1. [one clay nick or lull- Inn Feet <>v more in thickness. 
2. [one sandstone — 1<n feet or more in thickness. 
3. White claj and sand beds containing coal seams 800 
feel hi- more. 
♦Pacific Railroad Reports, vol. 5, pp. 164-173. 
