Mat 24, 1907] 



SCIENCE 



825 



of 30° to 40°. The sedimentary block which 

 constitutes the back (west) slope of the moun- 

 tain is affected by numerous faults, the chief 

 of which extend north and south, and consti- 

 tute the main fault scarp on the east side of 

 the range. At the foot of the range on the 

 west side, the sedimentary rocks are cut off 

 by quartz-monzonite-porphyry the intrusion of 

 which appears to have furnished the solutions 

 from which the ores were derived. Of in- 

 terest in this connection is the occurrence of 

 pyroxene intergrown with amphibole and 

 specularite together with quartz and calcite 

 along the boundaries of the sulphide ore bodies 

 with the inclosing limestone. 



The Santa Maria Oil District, California: 



Ealph Arnold. 



The Santa Maria oil district, comprising the 

 Santa Maria, Lompoc and Arroyo Grande 

 fields, occupies the central and northern por- 

 tions of the Lompoc and Guadalupe quad- 

 rangles, northern Santa Barbara County, and 

 the southern part of the San Luis quadrangle, 

 southern San Luis Obispo County. 



The San Eafael Mountains, 2,000 to 6,000 

 feet high, trend northwest across the north- 

 eastern portion of the area, while the Santa 

 Tnez Eange skirts the southern. Occupying 

 the angle between the two ranges are low hills 

 and broad valleys. The developed fields cover 

 the flanks of two of the low ridges in this 

 basin region, the main or Santa Maria field 

 proper being located on Graciosa Eidge, about 

 eight miles south of the town of Santa Maria. 



The formations involved in the geology of 

 the district include the Franciscan (Jurassic) 

 sandstone, shale, glaucophane schist, jasper 

 and intruded serpentine; Knoxville (lower 

 Cretaceous) conglomerate, sandstone and 

 shale; pre-Monterey (which may include both 

 Cretaceous and older Tertiary) conglomerate, 

 sandstone and shale; Sespe (Eocene or Oligo- 

 cene) sandstone; Vaqueros (lower Miocene) 

 conglomerate, sandstone and shale; Monterey 

 (middle Miocene) diatomaceous and clay shale 

 and volcanic ash; Fernando (Miocene-Plio- 

 cene-Pleistocene) conglomerate sandstone and 

 shale; and Quaternary gravel, sand, clay and 

 alluvium. 



Two structural systems prevail in the dis- 

 trict, those features in the northeastern por- 

 tion striking northwest and southeast, those 

 in the southern portion striking east and west ; 

 while in the intervening region are features 

 trending in a direction intermediate between 

 the two. Few faults of importance were noted 

 in the field. The productive territory lies in 

 a region of more or less gentle folds in the 

 central part of the area, the wells usually 

 being located along or near anticlines. 



The wells vary in depth from 1,500 to over 

 4,000 feet. In the Santa Maria and Lompoc 

 fields they obtain their oil from zones of frac- 

 tured shale or sandy layers in the lower por- 

 tion of the Monterey (middle Miocene) forma- 

 tion. The production of the individual wells 

 varies from 5 to 3,000 barrels. The gravity 

 of the oil ranges from 19° to 35° Baume, the 

 yield from the greater part of the field being 

 about 25° to 27°. In the Arroyo Grande field 

 the oil comes from sandstone at the base of 

 the Fernando and is of 14° gravity. 



Notes on the Oeology of Japan: Egbert An- 

 derson. 



This paper gave an outline of the general 

 topographic features and geological structure 

 of the Japanese islands. To sum up the main 

 points : The ground plan of the group was laid 

 during the earliest geological times, Archaean 

 gneisses and schists and a great thickness of 

 Paleozoic sedimentary, metamorphic and ig- 

 neous rocks being the basement complex. 

 Mesozoic, Tertiary and Quaternary formations 

 are wide-spread and diversified, having the 

 character of a superstructure over an older 

 land mass. The island chain is continental in 

 character, not chiefly of volcanic origin, al- 

 though volcanic activity has always been a 

 feature of its history. It is a country of long- 

 continued and great geological activity, as 

 shown by the variety of its rocks, by the pres- 

 ence of a thick column of strata representing 

 the earliest and latest as well as intermediate 

 times, by the metamorphism and excessive dis- 

 turbance of these strata as the result of re- 

 peated movements, by the presence of many 

 igneous intrusions and volcanic remains which 

 show that similar igneous forces as are at work 



