Fairbanks.] 



Geology of Point Sal. 



7 



is exposed. The strata are perfectly horizontal and seem to have 

 been lifted without any disturbance. A remnant of these beds of 

 similar character and horizontally bedded occurs on the summit of 

 the ridge where the road crosses, the altitude being 1,050 feet. This 

 outcrop almost overlooks the steep descent to the Old Landing. 

 Fragments of shells are scattered in many places over the surface 

 of this formation up to an elevation of 900 feet. The following 

 species were determined: Pupura canaliculata, Duel.; Chlorostoma 



Figure i. — Pleistocene mesa on the southern side of the Point Sal Ridge. 



brunneum, Phil.; Mytilus calif "orniens, Con.; Litnatia Lezvisii, Gld.; 

 Haliotis, sp. These species are all living. Remnants of a gently 

 sloping Pleistocene mesa also occur on the south side of the ridge. 

 These are particularly noticeable about the heads of the valleys which 

 have been eroded in the gypsiferous clays, and on the ridges be- 

 tween the small streams which head above the clays. 



At the head of the valley north of the dairy the rim of Pleistocene 

 is very narrow, and consists chiefly of fragments from the bitumin- 

 ous shales above. Springs impregnated with calcium carbonate 

 have thoroughly cemented the fragmental mass and formed beauti- 

 2 



