26 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4TH SER. 
indirectly traced into the McKittrick district. West of the 
Midway district the Coalinga beds occur on both sides of the 
range, on the one side dipping toward the Great valley and 
passing below the Midway wells, and on the other side dipping 
to the southwest and under the Carisa and Elkhorn valleys. 
Their structure at this point is that of a denuded anticline, 
though it is not likely that the two slopes were ever quite 
horizontal. The thickness of these beds on both sides of the 
range is very great,—hardly less than 4500 feet. 
Near their base they contain very coarse conglomerates and 
sandstones, among which may be found the characteristic 
fossils. The conglomerates often contain boulders of granite 
of immense size, some of them weighing 15 to 20 tons. The 
conglomerates at the base of the series range through several 
hundred feet of strata, of which they make up a large per- 
centage. The species thus far found in these beds are those 
typical of the Coalinga, and include forms not found else- 
where in great numbers. They are more abundant on the 
western than on the opposite side of the range, though they 
have also been found on the eastern side. On the western 
slope near the locality commonly known as “the Dome”, the 
following species have been found: 
Pecten crassicardo CONRAD Tamiosoma gregaria CONRAD 
Pecten estrellanus CoNRAD Chorus carisaénsis ANDERSON 
Ostrea titan CONRAD 
These beds have been followed northward along the western 
side of the range to the neighborhood of Simler. They pass 
in a synclinal fold below the Carisa valley and appear again 
on its western border. Near La Panza Springs an identical 
fauna has been obtained with the addition of such typical 
forms as: 
Chione temblorensis ANDERSON Lucina borealis LAM. 
Trophon sp. Astrodapsis tumidus REMOND 
Turritella sp. Astrodapsis whitneyi REMOND 
and many other species. Not far away, at the crossing of 
the San Juan creek, these beds overlie an immense thickness 
of Miocene strata including both the Monterey shales and the 
Temblor beds. In the foothills of the Midway district this 
