912 



SCIENCE 



[X. S. Vol. XXXI. Xo. 806 



sea bottom, may not the edaphic factor help 

 to explain the observed distribution, particu- 

 larly since the dark Mississippian limestones 

 of Utah and Montana are notably unlike the 

 contemporaneous rocks of Iowa? 



The lack of evidence on debatable points 

 throughout the paper is a constant source of 

 disappointment to the reader. Thus on page 

 454 it would be interesting to know what 

 leads the author to suggest central California 

 as the site of an inlet from the Pacific Ocean 

 rather than some other part of the coast. 

 The Paleozoic rocks are so highly meta- 

 morphosed or so deeply buried from Mexico 

 to Alaska that only here and there (as in 

 northern California and Oregon) are they 

 clearly recognizable, and to the average geol- 

 ogist there seems to be no ground for choos- 

 ing any particular spot for the purpose indi- 

 cated. This deficiency is probably one which 

 the author could not easily prevent. It is to 

 be remembered that the subject is over-large 

 to cover adequately in so brief a space. It 

 may be hoped that Mr. Schuchert will soon 

 find time to prepare a volume or volumes 

 under the same heading, in which he will give 

 the desired facts which support his views. 



Two things will tend to detract from the 

 confidence with which this important and 

 otherwise impressive paper will be received 

 by geologists in general. One is the non- 

 chalant way in which questions of a complex 

 nature are dismissed as if they were matters 

 of established belief. For example, on page 

 490 one finds the implication that the origin 

 of dolomite is a matter of common knowledge 

 whereas it is still an unsolved riddle to keen 

 students of the subject. Again on page 447 

 is the statement, " Oolites are formed in the 

 littoral region of seas between tides. . . ." 

 This may explain some oolites, but several 

 other explanations have been offered and it 

 can not be truthfully said that the subject of 

 the origin of oolites is yet understood. 



The second and more serious defect is the 

 assertive and dogmatic form in which many 

 a debatable matter is presented,. Examples of 

 this are abundant throughout the paper, but 

 the following will illustrate : (page 453) " Its 



syncline (Rocky Mountain sea) was due to 

 thrusting of the Pacific mass. . . ." There is 

 still much difference of opinion among the 

 best students of the subject as to just what 

 causes the warping of land surfaces. (Page 

 459) " Throughout the Paleozoic the north- 

 ern Atlantic waters were separated from 

 the southern Atlantic by the great conti- 

 nent Gondwana, uniting Africa and South 

 America across the medial region of the 

 present Atlantic. It is, therefore, not cor- 

 rect to speak of the northern Atlantic until 

 the present form of this ocean has been 

 attained. . . ." The existence of the Afro- 

 American land bridge, although indicated 

 by a considerable mass of evidence, is 

 denied by many whose opinions are worth 

 considering. (Page 495) " There was no 

 Cordilleran sea of this time " (late Mississip- 

 pian). In this case the unequivocal assertion 

 of the author can be as positively refuted since 

 a rich Kaskaskia fauna was discovered last 

 year in the Wasatch Mountains of Utah. 



In conclusion, and after offering these criti- 

 cisms, the reviewer desires to repeat that the 

 paper is a storehouse of information and a 

 large contribution to the subject — the fruit of 

 many years of careful study by a man well 

 qualified as a paleontologist and blessed with 

 unusual opportunities in the way of facilities 

 and associations. Even so soon after its ap- 

 pearance it is plain that the paper is stimu- 

 lating interest in the relatively new and still 

 plastic science of paleogeography, in which 

 much must be accomplished before firm foun- 

 dations can be reached. 



Eliot Blaokwelder 



University of Wiscoksin, 

 April 25, 1910 



SPECIAL ARTICLES 

 Webber's " brown fungus " of the citrus 



whitefly (^gerita webberi n. sp.) 

 H. J. Webber discovered this fungus in 

 1896 growing parasitically upon the citrus 

 whitefly at Manatee, Ela. He described in de- 

 tail the sterile form of the fungus.* This 



^ U. S. Dept. of Agr., Div. of Veg. Phys. and 

 Path., Bui. 13, 27-30, 1897. 



