32 TKANSACTIONS OF THE [OCT. 27, 



persons to occur near the pebble beach of Pescadero, and parti- 

 cuhirs were communicated tons in 1885 by Mr. J. W. Eedvvay, 

 so I did not personally examine this region. 



6. San Francisco. Extensive sand-dunes form a conspicuous 

 feature in the ocean suburbs of San Francisco. Powerful winds 

 from the broad Pacific drive the sand city-ward and formerly 

 threatened to submerge a shifting real estate — a region of "sand- 

 lots/' world-notorious through the pseudo-oratory of a mischiev- 

 ous demagogue. 



Recently scientific arboriculture has reclaimed a large tract 

 for the Golden Grate Park. Extensive dunes still remain, some 

 of them measuring 50 to 60 feet on tlieir steepest incline ; on 

 the lee side the sand lies at the angle of rest, which here is 31°, 

 the same as in Egypt, Bermuda, and the Hawaiian Islands. In 

 the dry season the sand is quite mobile, but, notwithstanding 

 these favorable conditions, it is utterly devoid of sonorous prop- 

 erties, owing to its shaly and siltose constitution. The beach 

 sand south of the Cliif House is also non-soAorous for the same 

 reason. 



7. Laguna Beach. This beach lies on the ocean about five 

 miles north of Grolden Grate, and was reached via Sancelito. The 

 sand here, too, is shaly and wholly non-sonorous. Reporting the 

 occurrence of non-musical sand maybe uninteresting, but is not 

 altogether superfluous, for negatives are of importance in estab- 

 lishing affirmatives. 



8. Mexico. Mr. W. Waddell, now in Brazil, but a resident of 

 Mexico for fifteen years, has furnished me with data of a sonorous 

 sand-hill in the Peninsula of Lower California. A gentleman of 

 accurate thought and a close observer of nature, he responded 

 to my pertinacious questioning in so satisfactory a manner as to 

 leave no doubt concerning the nature of the phenomenon and 

 the character of the locality. 



In the year 1885, just before the close of the dry season, Mr. 

 Waddell was with a party of Mexicans on a schooner fitted out 

 for the capture of turtles. They coasted along the Pacific shore 

 of Lower California and made landings at many points. About 

 €0 miles north of Cape San Lucas, the extreme southern end of 

 the Peninsula, the party landed, and one of them climbed to the 

 top of a dune to get a view of the neighborhood — in short, to 

 prospect for turtles — and observed a sound issuing from the dry 

 loose sand disturbed by his act. Mr. Waddell, standing near, also 

 heard the sound, and, having previously read of the Mountain of 

 the Bell, at once recognized the phenomenon. This dune is 

 about 70 feet high (memory-measure), and shaped like the half 

 of a lens ; its sides are covered in part with plants common to 



