372 CALIFORNIA ACADEMY OF SCIENCES. 



only one having the necessary conditions for their growth. 

 The nearest groves of the species are 21 miles N. W. and 23 

 miles S. W., across the bay, bnt some buried logs in San 

 Francisco County, about 14 miles distant, show that a few 

 ^rew there during past centuries. A few grew along San 

 Leandro creek, to a distance of six miles south, and w^ere as 

 Jarge as the others. 



Several sawmills were built soon after 1849, and every 

 accessible tree large enough for use was cut down. The 

 roots being almost indestructible, however, have sprouted 

 vigorously, sending up 10 to 20 sprouts about each stump, 

 rand these now shade the ground around springs more dense- 

 ly than the large ones, though probably not condensing so 

 much moisture from fogs. They are now a foot thick, fifty 

 feet or more high, and sometimes covered with cones, show- 

 ing no tendency to die out. The stumps are mostly about 

 12 feet thick, and the old trees probably averaged 200 feet 

 ihigh. Unfortunately, this magnificent tree growls so much 

 slower than some others that it is not a favorite, and the 

 settlers grub or burn out all those on land suited for cul- 

 tivation, besides destroying thousands every year for dec- 

 larative uses. 



I have described this grove particularly because its moist, 

 <cool locality seems exactly suited for land pulmonates, and 

 yet none are found above 1,000 feet on the peak, and only 

 two si^ecies there, Nos. 5 and 11, one a Limacoid, the other 

 very thin-shelled, but not found in the drier regions east- 

 ward. 



The reason indicated by these two species for absence of 

 ■others seems to be the want of lime, and to confirm this we 

 find at about the lower limit of redwoods on San Leandro 

 Creek, other species of the coast range, Nos. 25, 26 and 31, 

 {26 very small, but typical), appearing where branches from 

 the east bring down lime from the more eastern ridges. 



The sandstone of the peak is supposed to be cretaceous, 

 but contains no fossils, while the miocene strata three miles 



