Septembee 18, 1908] 



SCIENCE 



379 



tHe theory, once granted, than to grant it and 

 its retinue of corollary assumptions. But the 

 mere novelty and unfamiliarity of the con- 

 ception, not to say the strange difficulty that 

 the reader experiences at first in orienting 

 himself in a pendulating world, need hardly 

 of itself invite to indifference or contempt. 

 A hypothesis, however unproven or unprov- 

 able, which puts into such new and clear light 

 so many obscure phenomena seems to me to 

 deserve, at least at the hands of students of 

 distribution, a modicum more of attention 

 than has recently been accorded it by a 

 British reviewer. As for the ultimate dis- 

 position of such theories as those of Eeibisoh 

 and Kreichgaur, that is clearly more likely to 

 fall within the province of astrophysics than- 

 of faunistic biology. 



Egbert E. Eichaedson 

 Department of Bionomics, 

 Stanfoed Univebsity 



comet is of course above the horizon in north- 

 ern latitudes through the whole night. 



Edwin B. Feost 

 Yerkes Observatoet, 

 September 4, 1908 



MOREHOUSE'S COMET 



A COMET was discovered photographically 

 at the Yerkes Observatory on the evening of 

 September 1, by Professor D. W. Morehouse, 

 of Drake University, Des Moines, la., who has 

 been engaged in graduate work during the 

 summer under the direction of Professor Bar- 

 nard. 



The comet's position on the three plates 

 simultaneously exposed on that night was ap- 

 proximately: E. A. 3" 20°'; Dec. North + 66°. 



Several photographs were also obtained by 

 Professors Barnard and Morehouse on Sep- 

 tember 2 and 3, from which quite accurate 

 positions will be determined. The tail is 

 shown on the plates for a length of about six 

 degrees, and exhibits some interesting struc- 

 ture. Although the comet made a strong im- 

 pression on the discovery plates, it was faint 

 visually when seen on the following night, 

 and was without any definite nucleus. The 

 coma was not large, but was uniformly diffuse. 



A micrometric position was obtained with 

 the 12-inch refractor by Mr. Fox, as follows: 

 Sept. 2, G. M. T., 17" 45", E. A. = 3" 21" 55'; 

 Dec. = + 66° 52' 24". 



The motion is thus seen to be toward the 

 north, with a slight westerly component. The 



SPECIAL ARTICLES 



NOTE UPON THE STEUCTUEE OF THE SANTA 



CATALINA GNEISS, ARIZONA 



The extensively-developed pre-Cambrian 

 gneiss of the South side of the Santa Cata- 

 lina Mountains near Tucson, Arizona, is re- 

 markable for its tabular form; its regular 

 stratification; its altitude at low angles; its 

 broad flat surfaces and in places, for its ex- 

 treme foliation, passing from coarse grained 

 tabular granitic-gneiss into micaceous, seri- 

 citic and hornblende schists. Seen from a 

 distance, especially from the locality known 

 as Gibbon's Eanehe, the croppings appear like 

 ordinary stratified sandstones and shales. 

 Close inspection reveals an elongated dravim 

 out and flattened structure, which it is the 

 special object of this paper to note. 



The whole series appears to have been 

 elongated under great pressure, resulting in 

 flattening and spreading out into thin layers 

 with a consequent reduction of thickness and 

 an increased lamination. 



I purposely refrain from describing this 

 modification of form as a " flow " or as " flow- 

 structure " for these terms convey the im- 

 pression of a much more mobile condition 

 than existed and of supei-ficial movement 

 rather than of the interior elongation by 

 stretching under great pressure of a deeply 

 seated mass of comparatively solid rock. 



The compression and extension are shown 

 in several ways, but specially by the elonga- 

 tion of nodules of feldspar ; by sheets of quartz 

 which seem to have been rolled out like dough 

 and impressed by nodular masses of feldspar 

 above and below. 



The phenomena remind the observer of the 

 curiously elongated rocks in California; the 

 " grave-stone slates " and sandstones of the 

 middle gold region, which are there uplifted 

 at high angles, while in the Catalina gneiss 

 the dip-as gentle, approaching horizontality. 



