302 



PROCEEDINGS OF THE CALIFORNIA 



Mr. Conrad. Id riding from the Ranch house of Tejon to Fort Tejon, on Mr. 

 Blake's trail, Professor Brewer and myself collected upward of forty species of 

 mollusca in less than one hour, and without diverging ten feet from our route ! 



The Californian Cretaceous formation is easily separable into two main divi- 

 sions. The older of these, designated in the Beport as " Division A," is the 

 equivalent of the upper portions, Nos. 4 and 5, of Meek and Hayden's section 

 in Nebraska, and the later beds of New Jersey and the Gulf States. It is possi- 

 ble that this group may be separated hereafter into two sub-groups ; but that 

 has no bearing on the question at issue. The upper or more modern member, 

 found overlying the lower one conformably in various places, as about Monte 

 Diablo and at Martinez, has no apparent equivalent in America. It is probably, 

 however, the American representative of the Maestricht beds, the ' Danien ' of 

 French authors. It is not a transition from Cretaceous to Tertiary, but is the 

 most modern member of the former, formation. 



It has many points in common with the Maestricht beds of Europe. It con- 

 tains but a single species, so far as known, of the complex-chambered group of 

 Cephalopods. A solitary ammonite, represented by half a dozen specimens, 

 has been found by myself, in place, even to the very top of the formation. 



Of 280 species of fossils recognized and named in the Californian Cretaceous 

 rocks, 107 are found in this upper member. Of these, 84 are peculiar, and 23 

 are found in common between undoubted members of this group and undoubted 

 members of the older group. Besides this, I was fortunate enough to discover 

 a locality near Clear Lake, this fall, where, within a space of two feet, I found 

 an admixture of upper and lower forms, proving the existence of a transitionary 

 bed or perhaps group of beds. The following table will exhibit at a glance the 

 grouping of species at each of the principal localities ; showing at the same 

 time which species are found in tbe intermediate deposit, and which exist in 

 common in both the upper and lower divisions. The various localities are de- 

 signated by letters, as follows : M, Martinez ; C, Clayton to Marsh's ; T, vicinity 

 of Fort Tejon ; G, a locality 10 miles west of Griswold's near New Idria ; 

 I, New Idria ; D, San Diego ; L L, Lower Lake Village, 1 mile S.E. of the town. 



TABLE OF SUBDIVISIONS OF CRETACEOUS FORMATION. 



