442 BOWEX AND AUROUSSEAU FUSION OF SEDIMENTARY ROCKS 



of arkose. It is rather closely paralleled in composition by an aplite 

 from Siberia (Table II, number 4), but its norm (Table III, number 3) 

 shows the same departure from typical igneous composition as do most 

 sediments, though in this case it is of very moderate degree. 



Systematic Position of the fused Samples 



The analyses of the fused cores show that both differ in composition 

 in the same way from ordinary characteristic sedimentary material (see 

 Table III). The principal feldspar identifiable under the microscope 

 in the original sediment of the Montezuma core is a basic plagioclase, 

 but the analysis shows that the alkaline feldspars are much more abun- 

 dant than the calcic. It can only be concluded that the finer-grained, 

 so-called claylike, matter of the arkose and of the shaly layers in it is in 

 reality but moderately kaolinized alkaline feldspars. Unquestionably 

 the sediment is the result of processes in which rock comminution domi- 

 nated oyer rock decay. The same would, no doubt, be true of the origina I 

 sediment of the "Meyer 6" well as shown by the analysis of the core. 



Table III. — Nor'mative Compositions and Systematic Positions of Cores 



12 3 



Quartz 22.6^ 25.26 25.20 



Corundum 3.67 4.49 1.43 



Orthoclase 12.79 12.79 18.35 



Albite 28.82 29.34 31.44 



Anorthite 15.29 15.29 11. 6S 



Hypersthene 14.60 11.06 10. 75 



Ilmeuite 1.22 1.37 0.61 



Apatite 0.51 0.40 0.35 



Pyrite 0.20 



Water 0.26 0.19 



Sum 100.00 100.00 100.00 



"II. 4. "3. 4. (1)11.4. '3. 4. I(II) .4.2. (.3)-!. 

 Toiialose. Tonalose. Lassenose. 



1. Fused core, Montezuma well, near Suisun, Solano County, California 

 (number 3, Table I). 



2. Hypothetical result of fusion of Montezuma sediment (number 3, Tabic 

 IV). • 



3. Fused core, "Meyer 6" well, Santa Fe Springs, Los Angeles County, Cali 

 fornia, deducting metallic iron (number 3, Table II). 



As a result of this fact, these cores depart but little in composition 

 from an igneous reck. Tlie Meyer core has already been compared wilh 

 an aplitic rock. In Table lA^ the fused product from the Montezuimi 



