On the Subdivisions of the Cretaceous Formation in California.
BY WM. M. GABB.
The recent appearance of a check list published by the Smithsonian Institute, and entitled “Check List of the Invertebrate Fossils of North America—Eocene and Oligocene—by T. A. Conrad,” renders it necessary that I should state more clearly than has been done heretofore, the relations between the two members of the Californian Cretaceous rocks; and should give all of the proofs that have yet presented themselves, in support of my views.
In 1856, Mr. Conrad published a paper in Vol. 5, Pacific Railroad Reports, pages 320, et seq., in which he described fifteen shells from the “Eocene” rocks of the Cañada de las Uvas, near the present site of Fort Tejon. Of these, eleven were considered by that author as being new to science. The other four were referred to previously described Eocene forms.
These specimens were procured by Mr. Wm. P. Blake, geologist of the expedition. They were obtained from a single boulder, the only one found by that gentleman.
In consideration of the scanty material, it is by no means surprising that Mr. Conrad should have made the determination that he did. The fossils of this locality, and, in fact, of this member of our Californian rocks, have a marked Tertiary aspect. This holds good, both as applied to the appearance of the specimens and also to the grouping of the genera. Mr. Conrad’s reference of these fossils to an Eocene age was perfectly justified by the light that he then possessed. Any other palæontologist, with the same specimens, would no doubt have done as he did. But I propose to prove that, after having studied this formation for five years, both in the field and in the closet—both palæontologically and stratigraphically—after having traced it upwards of four hundred miles, and after having collected fossils from it at a dozen localities, I, on the other hand, am perfectly justified in pronouncing it most unequivocally Cretaceous.
It is, to use a mild term, rather surprising that Mr. Blake, from whom Mr. Conrad obtained his material, should not have collected more specimens. According to his report, Mr. Blake reached the depôt camp at Tejon, on the third of September, 1853, and did not leave that vicinity until October 10th. During that time he traversed the distance between Tejon and the Cañada de las Uvas, four times. I am familiar with every foot of the ground on which he camped or on which he travelled; and I speak from personal observation, when I say that in going from one point to the other he could not avoid passing thousands of boulders and pebbles, full of fossils, similar to the single one sent to Mr. Conrad. In 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 divisions. The older of these, designated in the Report 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 possible 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 contains 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 the intermediate deposit, and which exist in common in both the upper and lower divisions. The various localities are designated 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; LL, Lower Lake Village, 1 mile S.E. of the town.
TABLE OF SUBDIVISIONS OF CRETACEOUS FORMATION.
| Upper Division. | Intermediate Beds. | Lower Division, and Remarks. | |
|---|---|---|---|
| Callianassa Stimpsonii | C. T. | Chico. | |
| Aturia Mathewsonii | M. C. T. | Martinez. | |
| Nautilus Texanus | C. | Shasta Co. | |
| Ammonites, n.s. | C. M. | Curry’s; Benicia; Martinez. | |
| Typhis antiquus | M. T. | ||
| Fusus Martinez | M. T. | ||
| F. Mathewsonii | M. C. | Curry’s. | |
| F. Diaboli | C. | ||
| F. aratus | M. | ||
| F. Californicus | C. T. | LL. | |
| Hemifusus Hornii | T. | ||
| H. Cooperii | C. D. | ||
| H. Remondii | M. C. T. G. | ||
| ? Neptunea supraplicata | C. D. | ||
| N. gracilis | M. | ||
| Perissolax brevirostris | LL | Many localities. | |
| P. Blakei | M. C. T. | ||
| Turris Claytonensis | C. T. | ||
| Turris raricostata | C. | (varicostata by error in Rep.) | |
| Cordiera microptygma | T. | ||
| Tritonium Hornii | C. T. | ||
| T. Diegoensis | D. | ||
| T. paucivaricatum | T. | ||
| T. Whitneyi | T. D. | ||
| Buccinum liratum | M. | LL | |
| Nassa cretacea | M. T. G. | ||
| Pseudoliva lineata | M. | ||
| Pseudoliva volutæformis | T. | ||
| Olivella Mathewsonii | M. T. G. C. | ||
| Ancillaria elongata | C. D. | ||
| Fasciolaria læviuscula | C. | LL | |
| F. sinuata | T. D. | ||
| F. Io | T. | ||
| Mitra cretacea | M. | ||
| Whitneya ficus | T. | ||
| Ficus mamillatus | T. | ||
| Natica Uvasana | T. | ||
| Lunatia Shumardiana | LL | Martinez and elsewhere.[29] | |
| L. Hornii | T. | ||
| L. nuciformis | C. T. (D.?) | ||
| Gyrodes expansa | LL | Almost everywhere. | |
| Neverita secta | T. | ||
| N. n.s. | G. I. | ||
| Naticina obliqua | M. T. | ||
| Amauropsis alveata | M. C. T. G. D. | LL | Curry’s; S. of Mt. Diablo. |
| Morio tuberculatus | M. T. C. G. D. | ||
| Scalaria (Opalia) Mathewsonii | M. | ||
| Niso polita | M. T. | ||
| Cerithiopsis alternata | M. C. | ||
| Architectonica cognata | M. C. T. | ||
| A. Hornii | T. | ||
| Margaritella crenulata | D. | ||
| Conus Remondii | M. C. T. D. | ||
| C. Hornii | T. | ||
| C. sinuatus | T. | ||
| Rimella canalifera | M. T. | ||
| R. simplex | C. D. | ||
| Aporrhais angulata | M. | ||
| Cypræa Bayerquei | M. C. | ||
| Turitella Uvasana | M. C. T. G. | ||
| T. Saffordii | LL | M. and Solano Co. | |
| T. infragranulata | M. | ||
| Galerus excentricus | M. C. T. D. I. | LL | |
| Spirocrypta pileum | T. I. | LL | |
| Gadus pusillus | M. T. | ||
| Dentalium Cooperii | M. D. | Curry’s; S. of Mt. Diablo. | |
| D. stramineum | M. D. | Curry’s; S. of Mt. Diablo. | |
| Bulla Hornii | T. | ||
| Cylichna costata | M. C. T. D. | M., Texas Flat, and many other localities. | |
| Megistostoma striata | M. | ||
| Martesia clausa | G. | Pence’s, Texas Flat, etc. | |
| Solen parallelus | M. C. T. | ||
| Solena Diegoensis | D. | ||
| Corbula Hornii | T. | ||
| C. parilis | G. M. D. | ||
| Neæra dolabræformis | M. | ||
| Mactra Ashburnerii | M. C. T. | Nearly everywhere in both Divisions. | |
| Gari texta | M. | ||
| Tellina longa | M. C. T. | ||
| Tellina Remondii | C. T. | ||
| T. Hoffmanniana | G. | M., Pence’s, and elsewhere. | |
| T. Hornii | T. | ||
| T. Californica | C. T. | ||
| Meretrix Uvasana | M. C. T. I. G. D. | ||
| M. Hornii | T. | ||
| M. ovalis | T. | ||
| Dosinia elevata | T. | ||
| D. gyrata | M. C. T. G. | ||
| Tapes Conradiana | G. M. T. | LL | |
| T. quadrata | M. T. | ||
| Cardium Cooperii | M. T. D. | ||
| C. Brewerii | M. C. T. G. | ||
| Cardita Hornii | M. C. T. I. G. | ||
| Lucina cumulata | T. | ||
| L. cretacea | C. | ||
| Mysia polita | M. C. I. | ||
| Crassatella grandis | M. T. | LL | |
| C. Uvasana | T. | ||
| Mytilus ascia | T. | ||
| Modiola ornata | M. C. T. I. | ||
| Septifer dichotomus | T. | ||
| Crenella concentrica | M. | ||
| Avicula pellucida | M. G. | LL | S. Louis Gonzaga. |
| Arca Hornii | T. | ||
| Cucullæa Mathewsonii | C. | LL | M. |
| Barbatia Morsei | D. | ||
| Axinæa sagittata | M. T. G. | ||
| A. Veatchii | LL | M., Tuscan Springs, etc. | |
| Nucula (Acila) truncata | M. T. | Everywhere. | |
| Leda protexta | M. C. T. G. | M. | |
| Placunanomia inornata | D. | ||
| Flabellum Remondianum | C. |
On studying the foregoing table, the following deductions present themselves: 1st, that the rocks of the upper division, at the various localities quoted, are all of the same geological age; and 2d, that they are intimately connected with the older groups by a passage of nearly a fifth of all the contained species of fossils from this, either into the intermediate beds, or into the lower group itself.
In anticipation of a possible objection that may be raised here, it will probably be as well, before going further, to state that in the Division B, there has been no confounding of two groups. The same grouping of species extends to the extreme upper limits of the fossiliferous rocks, which are everywhere overlain by an immense deposit of non-fossiliferous sandstones. Another objection, which has already been raised, that the acknowledged Cretaceous fossils have become mixed with more modern species by the breaking up and re-cementing of an older formation, I shall not even attempt to refute. Had such been the case, I would ere this, in common honesty, have acknowledged it.
In support of the two conclusions arrived at above, we have the following synopsis of the table:
Of the 107 species of fossils found in Division B, 44 are found at Clayton, 67 at Tejon, 54 at Martinez, 22 at San Diego, 18 near Griswold’s, and 7 near New Idria. It is not intended to be understood that these are all of the species found at these localities; but that, up to the present time, these are all that have been identified or described. Future work will undoubtedly change the above figures.
Of the species found at the above localities, 50 are peculiar to one or another locality; 29 are found at two localities only, 14 at three localities, and 14 at four localities or more.
Taking the three typical localities, Martinez, Clayton and Tejon, 21 species are common to Martinez and Clayton, 30 to Martinez and Tejon, 25 to Clayton and Tejon, and 20 are found at all three localities.
Now, having given what I believe ought to be considered proof conclusive to any candid mind in support of my first proposition, I shall endeavor to establish the second.
It will be seen that 16 species, found in the upper member, also extend into the older group, Division A. In addition to this, at the locality near Lower Lake Village, Lake County, besides several species encountered for the first time, I found 15 species in the same bed, within a superficial area of two feet. Of these, 3 were previously known to be common to the upper and lower division. Besides these 3, 7 of them were common to this locality, and localities of Division B, and the remaining 5 were, before this discovery, considered peculiar to the lower member. One of these 5 is found in the Mississippi Valley, in the “Ripley Group,” and another belongs to a peculiarly Cretaceous genus.
As to the species found at the several typical localities, independent of each other, and which would serve to show their individual relations to the older formation without corroborative evidence, Clayton has 10 species in common with Division A, Tejon has 7, and Martinez 11. With the Lower Lake bed, Clayton has 5 species in common, Tejon 5, and Martinez 6.
In glancing over Mr. Conrad’s “check list,” I find that out of the 107 species found in his “Older Eocene of California,” he has only included 74 in his enumeration. He has omitted Callianassa Stimpsonii, Ammonites n. s., Nautilus Texanus, Cylichna costata, Mactra Ashburnerii, Cucullæa Mathewsonii, Nucula truncata, and Leda protexta; eight species, which I mentioned in the Journal of Conchology, (Vol. 2, p. 88) as being found in common in the two members of the Cal. cretaceous, stating distinctly the localities in which they had been found. At the same time he includes five other species, from the same list, in his Eocene catalogue. Whether this be carelessness, or an unfair avoidance of a difficulty, I leave to others to decide. It is far easier to ignore such a difficulty than it is to explain it away.
In regard to the distribution of the genera and species in this and the associated rocks. All of the species are peculiar to this group, or to this and underlying rocks; not one has been found associated either with living forms, or with species known to occur in the recognized Tertiaries of California. Five of the genera are peculiar to the Secondary. An Ammonite ranges entirely through the group to the top of the highest fossiliferous strata. The genera Perissolax, Gyrodes, Margaritella, and the sub-genus Anchura, of the genus Aporrhais, are all recognized as strictly characteristic of the Cretaceous; so much so, that the presence of a single undoubted representative of either of these genera would be strong presumptive evidence of the Cretaceous age of any rocks in which it might be found. On the other hand, the presence of such genera as those in the list given below, would point to a very modern era in the Cretaceous, to say the least.
It must be borne in mind that we have much to learn yet in palæontology, especially in the matter of the vertical range of genera. Every year we find genera, nay, whole families, extending themselves beyond what had been fixed by previous authors as their limits. A few years ago, the presence of mammalian remains was considered characteristic of the Tertiaries. Now we know of Marsupials in the Trias, and who dare say that we cannot find mammals in palæozoic rocks? I therefore maintain, that though we have here such genera as Aturia, Typhis, Cordiera, Pseudoliva, Nassa, Mitra, Ficus, Morio, Cerithiopsis, Cypræa and Galerus, still, the only inference that can be drawn is, that the group is on or near the verge of the formation, a sort of prophetic member, presaging by some of its genera the formations to come, but indissolubly bound by specific ties with the eras preceding.
[29] This species was referred by inadvertence to Div. B. instead of A. This is the first time it has been found beyond the limits of the lower member.
Prof. Blake stated that he considered the collections made by him, in and near the Cañada de las Uvas, as not meager. There was a sufficient number of species to make a quarto plate of figures.
Prof. Blake read the following notice: