Geology of California. — Turner. 307 
and the shore was moved farther to the east, the character of the 
deposits at Sioux City changed, but coarse, cross-bedded sand- 
stones and other littoral deposits, charged with leaves and twigs 
of forest trees, must still have been formed in proximit}^ to the 
new shore lines. Even while the chalk and limestone of the 
Niobrara epoch were being precipitated over western Iowa, from 
solution in clear sea water that contained no trace of sediment, 
sandstones and shales containing numerous impressions of leaves 
and branches of terrestrial plants must still have piled up along 
that more remote eastern shore. But if the shore deposits of the 
Niobrara epoch could now be found, it is probable that every com- 
petent geologist or paleontologist would refer them unhesitatingly 
to the Dakota group. Deposits absolutely synchronous ma}- 
present very wide extremes of lithological and paleontological 
characteristics. It is possible, I think, to recognize a law which I 
have not seen expressly formulated, but which may run some- 
thing in this wise: — Synchronous deposits of the same geologic 
basin are more likely to present uniform lithological and paleon- 
tological characteristics if the geologist traces them along a line 
parellel to the shore of the basin. If the observations are made 
along a line that is radial to the geologic basin or at right angles to 
the trend of the shore, the different parts of absolutely synchronous 
beds are almost certain to vary in lithological and paleontological 
characteristics so much as sometimes to make it appear that differ- 
ent parts of the same bed belong to different geologic epochs. 
This law ma}' have greater force in connection with the study 
of Mesozoic and Cenozoic strata tlian in the study of the more 
ancient terranes, but even among the Puleozoics it must frequentl}' 
have an important application. 
SOME RECENT CONTRIBUTIONS TO THE GEOL- 
OGY OF CALIFORNIA. 
By H. W. Turner. AVashington, D. G. 
Geology of the Mother Lode Gold Bell: by Hakoi.d W. Faiku.^nks; 
American Geologist, vol. vli., 1891, pp. 200-222. 
In this paper Mr. Fairbanks gives the chief results of a sea- 
son's field work along the Mother lode. The author shows a famil- 
iarity with modern lithology, and the paper may be regarded as 
the most important contribution to the geology of the Mother lode 
