Anderson.] 



Point Reyes Peninsula. 



121 



The relation of the geology of Point Reyes to these questions 

 is direct, and it is regretted that a more complete treatment of them 

 is beyond the scope of the present study. At best only a few 

 suggestions can here be made. 



The peninsula embraces more territory than is covered by the 

 study represented in this paper, and more than is locally under- 

 stood by the term. 



Botindaries. — There is little difficulty in defining the boundaries of 

 the field. The western border of the peninsula forms a long and 

 gentle curve concave toward the ocean, extending north and south 

 for about twenty miles. Its eastern boundary is mainly formed by 

 the shore of Tomales Bay, a long and narrow inlet extending in a 

 southeast direction for almost twenty miles. This bay, which is 

 hardly a mile in width at any point, occupies a portion of a singular 

 rectilinear depression that continues beyond the limit of tide-water 

 in a low valley until it meets the axis of Baulinas Bay twelve miles 

 to the southeastward. The low ground of this depression forms the 

 neck of the peninsula, but as this territory was not all included in 

 the present examination, the remainder of the eastern boundary was 

 drawn at Bear Valley, which extends in a southerly direction to the 

 ocean from near the head of Tomales Bay. The southern boundary 

 of the field is formed by the shore of Drake's Bay, which describes 

 a broad curve open toward the south. From the northern limb 

 of Drake's Bay a system of shallow inlets extends for four or five 

 miles toward the heart of the peninsula like the outspread fingers 

 of a great hand. This system of inlets is locally known as Lamen- 

 teur Bay, and on the charts of the Coast and Geodetic Survey, 

 Drake's Estero. The peninsula as thus outlined is almost an equi- 

 lateral triangle, with its southern and western sides somewhat gently 

 curved. 



Literature. — Whitney mentions 1 in his report published in 1865, 

 occurrences of granite and white slate on the peninsula of 

 Punta de los Reyes, and speaks also of crystalline limestone and 

 schists, and of the well-marked depression occupied by Tomales 

 Bay, the valley of Arroyo Olemus Lake, and the Bay of Baulines. 



1 Geological Survey of California, Vol. r, pp. 84-5. 



