68 



SCIENCE 



[N. S. Vol. XXVII. No. 



(which consisted of Mr. Richard Tjader and 

 Mr. Lang, accompanied by 100 negro porters) 

 proceeded 327 miles inland by the Uganda 

 Eailroad to Nairobi. A strip of territory one 

 mile on either side of the railroad is set aside 

 as a government game preserve, and is a place 

 of refuge for mixed herds of antelopes, zebras 

 and ostriches. 



After spending a month collecting with 

 great success on the Athi Plains, the expedi- 

 tion moved northwest into the Eift Valley, 

 encamping at Kijabe and at various points in 

 the lake country. 



Thence the course was southeast over the 

 Laikipia Plateau to Mount Kenia (18,000 

 feet), which the party ascended to a height of 

 14,000 feet. Lack of provisions, however, 

 compelled a return to the railroad, whence the 

 party proceeded to the coast, stopping to col- 

 lect at intervals. 



Four and a half months' collecting netted 

 the expedition a total of about 500 skins of 

 birds and mammals. The most noteworthy of 

 the latter was the skin and skeleton of a fine 

 bull elephant carrying 160 pounds of ivory, 

 4 rhinoceroses, 1 buffalo, 2 giraffes, one of 

 which is unusually large, 8 zebras representing 

 different districts, and a fine series of ante- 

 lopes. Lions, spotted hyenas, aard-wolves and 

 other carnivores were also taken. Mr. Lang 

 also secured a remarkable series of photo- 

 graphs illiistrating the flora, fauna and 

 ethnology of the region. The talk was well 

 illustrated with colored lantern views. 



EoY Waldo Miner, 



Secretary 



THE GEOLOGICAL SOCIETY OF WASHINGTON 



At the 194th meeting of the society on 

 October 30, 190Y, Mr. P. E. Wright exhibited 

 a model for use in the study of crystal optics 

 and also described a new method for measur- 

 ing extinction angles of minerals in the thin 

 section. 



Regular Program 

 A Visit to the Alps: Mr. Bailey Willis. 



Mr. Willis gave an account of a trip in the 

 Alps during August and September. He 

 stated that he had investigated the geological 

 structure of the northern or front Alps and of 



a part of the Bernese Oberland with reference 

 to the character of the great overthrust faults. 

 He outlined his results in a broad way, but re- 

 served more definite discussion for future pre- 

 sentation to the society. An especially pleas- 

 ing feature of the trip was the cordial and 

 generous assistance rendered by Swiss geolo- 

 gists. 



A Comparison of some Paleozoic and Pre- 



Camhrian Sections in Arizona: Mr. F. L. 



Ransome. 



The Paleozoic rocks of the Grand Canyon 

 of the Colorado south of the Kaibab Plateau 

 rest with conspicuous unconformity upon the 

 Algonkian sediments and upon the basal crys- . 

 talline rocks. Between the Algonkian sedi- 

 ments (Unkar and Chuar terranes) and the 

 crystalline rocks is another great uncon- 

 formity. Considerable confusion has arisen 

 iu the literature of the pre-Unkar crystalline 

 rocks which Walcott called the Vishnu series 

 and described as metamorphosed sediments. 

 These ci-ystallines, from the point where they 

 emerge from beneath the Unkar south of 

 Vishnu's Temple to the foot of the Bright 

 Angel trail and west of that point, are dark, 

 fine-grained gneisses cut by red granite and 

 are probably all Archean. There appears to 

 be no ground for describing the Vishnu as 

 " bedding quartzite " or as metamorphosed 

 sediments, and the vertical bedding referred 

 to by Powell and Walcott is gneissic banding 

 or foliation. 



On the basis of Powell's and Walcott's char- 

 acterization of the " Grand Canyon schists," 

 or Vishnu, as metamorphosed slates and quart- 

 zites, certain crystalline schists in the Brad- 

 shaw Mountains, and in the Globe, Clifton 

 and Bisbee districts, which are clearly meta- 

 morphosed sediments, and which are uncon- 

 formably beneath the Cambrian (Tonto), have 

 been tentatively correlated with the Vishnu. 

 There is, however, little real warrant for this 

 correlation if the Vishnu is not an altered 

 sedimentary series. It is suggested that the 

 Pinal schist of Globe, Clifton and Bisbee and 

 the Yavapai schist of the Bradshaw Mountains 

 may be equivalent in age to the Unkar and 

 Chuar groups in the Grand Canyon. In that 

 case, the great unconformity found at the 



