DIKES ALONG COAST WEST OF SANTA CRUZ 



247 



soft, and has the peculiar wavy banded structure mentioned above. 

 Plate 29, and figure 1, plate 30, show the peculiar wavy and columnar 

 structure at the southwest end of the Respini Creek dike. 



The wavy layers exposed in this dike strongly suggest flowage of the 

 sand in a liquid medium, and the columns are ajDparently the filled 

 necks of channels through the sand mass through which liquids and 

 sands were forced up from below and around which those sands wera 

 deposited, thus finally building up the entire mass of the dike. 



'^=^ 



m^^ 



^^ 







P-^=^=:^^^^Cr^^ 





%,.>.,,.. 



Figure 16. — Sandstone Intrusion at 1^9, Figure 10. 



Looking east. The wavy banded structure is shown in the vertical part of the intrusion at the 

 right of the picture, and also in the nnain mass of the intrusion at the left. Sea terraces are 

 shown in the background. At the top of the sea-cliff in the foreground the Pleistocene gravels 

 and sand rest unconformably upon the underlying diatomaceous shales. 



Near the top of the sea-cliff and resting on the sandstone is a large lentic- 

 ular mass of diatom shale, similar to the shales at either side of the intru- 

 sion. This fragment is indistinctly seen near the center of figure 2, plate 28. 

 Whether this shale is in place or was lifted up to its present position by 

 the intrusion of the sand is not apparent. The outcrop of the Respini 

 Creek dike, which has an approximate strike of north 45 degrees east, 

 can be traced for one-fourth of a mile from the coast. At the southern 

 side of the intrusion on the coast line the dip of the diatom shales is 



