85 



From Mr. Tallaut, specimens of Ambystoma, in- 

 sects, and the ovum of a Shark. 



From Col. Ransom, specimens of Sand-stone, Ser- 

 pentine, and Chromic Iron. 



A unanimous vote of thanks was tendered to Mr. 

 Frank Baker, for a donation of carpets for the rooms 

 of the Academy. 



San Francisco, March 17, 1856. 



President in the chair. 



Donations to the Cabinet. 



From Mrs. T. J. Nevins, specimens of flowers from 

 Alameda. 



From Mr. G. S. Morgan, Fossil Shells from Shoal- 

 water Bay. The thanks of the Academy were or- 

 dered for the above donations. 



From Mr. Tallant, specimens of JVassa, Asteor- 

 canthion, Grapsus, &rc, from North Beach. 



From Dr. Lanszweert, specimens of J\~otophithal- 

 mus tarodus, Esch., from Mission Dolores. 



Donations to the Library, 



From Prof. J. D. Dana, "Science and the Bible — a 

 Review of Prof. Lewis' ' Six Days of the Creation.' " 



From the Boston Society Natural History, their 

 Proceedings, pp. 283 to 278. 



A communication was received from Mr. T. J. 

 Nevius, giving an account of a thunder shower ob- 

 served at Alameda. 



Description of a new species of Ammonite and Bacu- 

 lite,from the Tertiary rocks of Chico Creek. By 

 Dr. John B. Trask. 



It is not without some hesitency that the announce- 

 ment, of tliese genera is made at this time, as occur- 

 ing in a more recent group than that assigned them 

 by paleontologists of the present day. This is done. 

 knowing well that the period at which they became 

 extinct, is placed far below that of the lowest of the 

 Tertiary groups. Still, it appears to me impossible 

 to place the rocks containing these fossils, in any 

 other than the period here given them, and as late at 

 least as the superior portions of the upper Eocene. 

 The associated fossils are for the most part of the 

 present existing genera and species upon the coast, 

 and if the per centage of existing genera is admitted 

 as a rule to fix the relative age of rocks of this char- 

 acter, then it will be necessary to carry these beds 

 into the Miocene periods. 



The rocks are composed of about twenty genera, 

 not more than two of which, do not exist upon the 

 coast at the present time, and it may be doubted 

 that those will yet be found. Eleven of those most 

 easily made out, and which belong to the cabinet 

 specimens, are figured in outline on the plate, (see 

 plate 11,) together with accurate drawings of the 

 jeots of this paper, numbered 1 and 1. A, 2 and 2. A. 

 plate 11 ; and will serve to convey a correct idea of 

 the fossils of the group. 



The figures in outline consist of cardium, tellina, 

 mactra, natica.buccinnum, fusus, purpura, cerithium, 

 turritella, &c. The bivalves not figured, consist of 

 veneres, cytherea,lutraria, and several other genera. 

 Had there been but a single specimen of thebaculite 

 and ammonite, their appearance in these rocks might 



have been considered purely an accidental circum- 

 stance, and occuring as a transported fragment from 

 the districts to the north, and one hundred miles 

 distant, where those genera abound. But as they 

 are not found in the rocks of the same character or 

 age, they cannot be attributed to that cause. 



When we consider their number, and the relation 

 they hold numerically to the associated fossils of the 

 group, and promiscuous distribution, we cannot do 

 otherwise than assign to them an age extemporane- 

 ous throughout, and that they lived and died in 

 those beds in which theirremains are now found. 



My attention was called to these fossils by Dr. A- 

 Randall, by whom they were found on Chico Creek 

 during the past winter, and by him placed in the 

 cabinet of the Academy. I have seen but one 

 ammonite from this locality, but he has knowledge 

 of three or more from the same place. 



After examining the Baculite presented by him, I 

 became convinced that the small cylindrical fossils, 

 so frequent in those rocks belonged to this genus, 

 and on inspecting the specimens in the cabinet, not 

 less than nine different specimens were counted. 

 Prior to this time, I had regarded those shells as 

 "lentalia, for which they would easiiy be mistaken, 

 from their small size and the character of the fossils 

 with which they are associated. 



If an erroneons diagnosis has not been made in re- 

 lation to the age of these rocks, (and of this fact I 

 entertain no fear) they become a matter of much 

 scientific interest, as they prove that the period at 

 which these animals existed, descends to a later day 

 than that now by general consent assigned them, 

 and these rocks will demonstrate that fact most in- 

 contestibly, 



The only question that can arise in this case is, 

 whether we shall conform to the strict scholastic 

 rule laid down, for the clasification of geologicMl 

 periods, and carry so extensive a group of decidedly 

 tertiary deposits clown to the cretaceous, with their 

 present existing genera with them ; or carry two 

 genera higher up in those periods, and give them 

 what they most unmistakably tell us, viz., a later 

 animate existence than before known. 



If the former case be applied, then it will become 

 necessary to modify our opinions relating to tertiary 

 rocks, particularly in this State, for most certain it 

 is that the fossiliferous beds of Chico Creek are more 

 recent than those of Ocoya (Pose Creek) Creek of 

 Tulare county, the fossils of which have recently 

 been examined by Mr. Conrad of Philadelphia, and 

 by him pronounced to be of miocene date. 



Ammonite (Lam) Chicoensis. Trask. 

 Plate II. Fig. 1 and 1. A. 

 Shell small ; with two and one-half whorls ; twen- 

 ty-three tertuous angulate costae. each second or 

 third rib terminating at the ventral edge of the out- 

 er whorl, the others pass beyond ; two rows of small 

 tubercles on the last whorl, the outer row and lar- 

 gest, situated on the dorsal edge, the inner row 

 situated about one-fourth of the depth of the whorl 

 from the dorsal edge, and becoming obsolete at the 

 eighteenth rib ; tubercles on the outer edge corres- 

 pond to the number of costae on the whorl, siphuncle 

 visible the entire length of the dorsum. Length, 

 eleven-twentieths; depth, nine-twentieths; width, 

 four-twentieths of an inch. Locality, Chico Creek, 

 Cal. 



Bacui.itk fLam; Ciiuoknsis. Trnsk. 



Plate II. Fig. 2 and 2. A. 

 Shells small ; thin ; compressed ; smooth ; latcro- 



