pliocene fresh water fossils. i7i 



The Santa Clara Lake Beds. 



Fossil fresh water shells have been found at several 

 points on both sides of this valley, and at different heights 

 above it, but sufficient specimens have not yet been col- 

 lected to determine the ages, elevations, disturbances, 

 etc., of the various beds. The oldest known is that at 

 San Jose Mission, where a ridge apparently of pliocene 

 date remains as a remnant of a thick bed of gravel and 

 alluvium once filling the greater part of the valley to a 

 depth of probably 300 feet above tides. The same de- 

 posit is seen at intervals from East Oakland along the 

 foothills southward on the east side of the valley, and less 

 abundantly on the west side to near Redwood City, but 

 does not everywhere contain fossils. It is considerably 

 disturbed in some places, usually by elevation of the 

 mountains since its deposit. A dry gravel bed in the west 

 end of Livermore valley may be of the same age, and 

 bones of land animals are found in many places, some of 

 them probably contemporaneous, some later. 



Dr. L. G. Yates first found the beds at San Jose Mis- 

 sion, and I have visited them. The species obtained are 

 the following: 



L Amnicola yateslana J. G. Cooper. Plate xiv, fig. 10 (Xo). 



2. Cochliopa rowelli? Txyon=^Pompholopsis? 



.3. Pomatiopsis intermedia Tryou. 



•i. Helix caUforniensis Lea, var. ramentosa Gonkl. 



As no extinct species except Amnicola yatesiana have 

 been found in the other deposits in Santa Clara County, 

 I will merely add a list of the species obtained from them, 

 and await further collections and surveys. This species 

 has also been found in a well bored in Tulare County at 

 1,058 feet depth, and once probably existed as abundantly 

 west of the Sierra Nevada asyl. longinqiia did east of 

 them, but is now extinct, as the latter is, except in Utah. 

 The above list is continued as follows: 



