416 



Popular Science Monthly 



The photograph with the man stand- 

 ing i)esi(Je a rork shows a perched 

 granite boulder left on a sandstone base 

 by a glacier which melted on a slope of 

 the famous Yosemite Valley, California, 

 a \ast gash in the 

 Sierra Nevada, 

 now believed to 

 have been largely 

 cut out by glacial 

 action. Since the 

 boulder was so de- 

 posited it has 

 changed but little. 

 The sandstone 

 pedestal, however, 

 is greatly weather- 

 ed and in the 

 natural course of 

 events, in a few 

 hundred or a thou- 

 sand \earspcrha]),s, 

 will further disin- 

 tegrate. Tiien the 

 boulder will be pre- 

 cipitated down the 

 steep slope of the 

 gorge into the can- 

 yon below. 



What are now 

 the beautiful 

 Tuolumne Mead- 

 ows of California 

 were formed by billions of tons of rock 

 and soil, including many great boulders 

 as large as houses, which were trans- 

 ported by glaciers from the Sierra 

 Nevada. Most of this material has 

 been formed into soil and grass, trees 

 and running streams all to make a 

 beautiful natural park. A few great 

 granite boulders still remain to be a 

 witness to the might of a glacier which 

 melted away long ago. 



One of the pictures shows a large 

 boulder which is beginning to dis- 

 integrate, wiiile the smaller boulder — 

 weighing perhaps a ton — is perched on 

 top of it, having rested in this position 

 for probably the better part of a thou- 

 sand centuries. Another of the photo- 

 graphs shows a large erratic boulder 

 resting on a rock outcrop in Mono 

 Valley, California. Undoubtedly it was 

 transported to this point from the 

 nearby Sierra at a lime when the ice 

 streams flowed strongly down the eastern 



A rypir;il Crevasse Cruiseii by the Earth- 

 quake Which Demolished San Francisco 



slope of this range to levels much lower 

 than those reached by the feeble glacier 

 remnants now existing near the summits 

 of the range. This boulder could have 

 been brought to its present position only 

 by some agency 

 not now present 

 and one that would 

 disregard topogra- 

 phy, riding over 

 irregularities in 

 land surface and 

 leaving erratic rock 

 fragments perched 

 in positions to 

 which water could 

 not transport 

 them. 



The famous 

 Balanced, or Rock- 

 ing, Stone of the 

 Garden of the Gods 

 in Colorado was 

 deposited in a 

 similar way by the 

 glaciers of the 

 Rocky Mountains. 

 It is a stone of very 

 large dimensions, 

 and so exactly does 

 it balance that un- 

 til lately it could 

 be swayed easily. 

 The continual rocking to which it was 

 subjected by thousands of tourists 

 ground away the base to such an extent 

 that to i)reser\e it as a curiositj' it was 

 cemented in place. 



A^' 



One of the Pranks of the San 

 Francisco Earthquake 



^BOVE is one of the crevasses caused 

 by the eartluiuake which almost 

 destroyed San I'rancisco. Earthquakes 

 are always terrif>ing e\ents, but they 

 are only excessively destructive of life 

 and property in case the territory 

 affected is thickly populated and highly 

 imjiroved. At this uninhabited point 

 the great eartluiuake of i()ofi resulted 

 only in a natural curiosity, but imagine 

 this rift occurring beneath the business 

 block of a pr<is(X'rous town! In another 

 place a quartiT of a mile of wagon road 

 was boilily removed ten or twelve feet 

 from tlic rest of the road. 



