78 



University of California Publications. 



I Geology 



too silieious and too low in alumina to be available for cement 

 manufacture. 



Clay. — The clay deposits are alluvial and occupy depressions 

 in the old river channel near Chittenden. The deposits cover 

 about thirty-five acres and have a maximum depth of forty feet. 

 This clay is of uniform texture and is dark blue in color. The 

 following analyses of samples from five different borings are 

 available for publication : 



Analyses of Clays. 



ABODE 



SiO a 59.80 51.62 51.88 52.79 63.26 



CaO 2.96 2.67 2.67 3.31 3.05 



MgO 2.92 4.24 4.29 4.27 1.40 



Fe 2 3 7.73 7.87 8.20 7.58 6.17 



ALO3 15.64 16.83 18.05 18.12 17.26 



S0 3 60 2.03 2.33 1.01 trace 



Loss 7.71 10.38 11.87 10.58 7.17 



Alkalies 2.64 4.36 .54 2.34 1.69 



100.00 100.00 100.00 100.00 100.00 



Average samples of the raw materials after being ground, 

 mixed into slurry and clinkered, and the clinker ground to 100 

 mesh, gave a cement of good color with a specific gravity of 3.28, 

 and the following composition which, it will be seen, falls 

 between the limits of the Chatelier and S. B. Newberry standards. 



Analysis of Cement. 



Si0 2 21.12 



AL0 3 6.11 



PeAi 3.37 



CaO 61.04 



MgO 1.11 



so, 1.01 



Stone. — The diorite is quarried extensively at Logan, just 

 south of the Pajaro River and on the Southern Pacific Railroad. 

 The quarry is owned and operated by the Granite Rock Company 

 of Watsonville, California. The rock is so fractured and shat- 

 tered that blasting is unnecessary, and this renders the stone 

 useless for decorative building purposes. It is used extensively, 

 however, for road-beds and concrete work. 



Sand. — The same company use a large quantity of Merced 

 sand for concrete work. 



