THE NAUTILUS. 51 



The ten mile descent of the mountain on its western side was com- 

 paratively easy as the road was in excellent condition. The weather 

 has been delightful since we have been here and trust that it will 

 continue so throughout our stay. 



Although the ground on the mountain's side was quite dry, care- 

 ful searching with the aid of a short limb of a tree, raking deeply 

 among the fallen leaves, revealed to us, quantities of the following 

 Helicies, all with the living animal within. 



Helix arrosa, nickliniana, Polygyra armigera and Selenites van- 

 couverensis. No fresh-water shells were found in the streams and 

 pools on the way over. In fact, I do not believe there are any in the 

 vicinity of this place, for I have been unable to secure a single speci- 

 men during the past six years. 



The tides so far, have been very good and several species have 

 been added to my collection, which are entirely new to me. 



The beach from the bluffs near the channel (entrance to the Bay 

 of Bolinas) out to the dangerous reef Duxbury reef is at inter- 

 vals composed of billions of particles of shells, ground so fine that 

 the casual observer would naturally suppose they were grains of 

 sand. Certain spots I have seen on the beach are almost wholly 

 composed of these diminutive bits to a depth of about five or six 

 inches. 



The reef upon which I had formerly seen attached thousands of 

 immense Cldoroatoma funebrale and fairly good sized Chrysodomus 

 dims are now almost destitute of the above named species. The 

 reason of their disappearance is unknown to me. The species ob- 

 served attached to the rocks and the blue clay at the present date 

 are Monoceros engonatum and Litoritta scutulata. M. encjonatum 

 predominating. Of Chlorostoma brunneum, I have gathered hundreds 

 at previous visits, from a point just a short distance from the reef in 

 a north-westerly direction. Not one in a living state have I found 



since arriving. 



Strolling up the sandy beach in the early morning, (4.30) until 

 we reached the stretch of mossy rocks which had been left bare by 

 the retreating tide, we secured dozens of the common edible clam, 

 Tapes staminea, which is sold by the sackful in the markets of San 

 Francisco. These were brought back to our camp and served at 

 breakfast. 



The Bay of Bolinas, which at one time was quite commodious, is 

 now almost completely filled with sand and mud. The channel, no 



