538 proceedings: geological society 



Interpreting irregular data. The manifestations of nature are of utmost 

 irregularity; of all sciences, that of agriculture is richest in data but 

 poorest in correlation. The most generally used method for discussion is 

 that of averages, but in biological and other fields this method is of little 

 value. The author has been quite successful in the application of the 

 integral of the probability curve to data of this character. Lantern 

 slides were shown to illustrate such application to data for turbidity of 

 Washington water before and after operation of filtration plant, and to 

 data showing number of leucocytes in morning and evening milk. The 

 paper was discussed by Messrs. Hersey and Swann. 



Upon invitation of the chair, Mr. C. E. St. John, of the Mt. Wilson 

 Solar Observatory, gave an informal report upon the social and scientific 

 features of the recent conference of the Solar Union at Bonn. He ab- 

 stracted briefly each day's proceedings. Reports were given by various 

 committees on solar radiation; standard wavelengths; solar atmosphere; 

 solar rotation, sun-spots and eclipses, and magnetic state of the Sun. 

 The speaker referred particularly to the favorable reception accorded 

 the work of Abbott and to the fact that the American contingent of 

 workers is bearing its fair share in the development of solar research. 

 The chair expressed the thanks of the Society to Mr. St. John for the 

 report. At 10.00 p.m. the meeting adjourned. 



J. A. Fleming, Secretary 



THE GEOLOGICAL SOCIETY OF WASHINGTON 



The 270th meeting of the Society was held in the Cosmos Club on 

 April 23, 1913. 



An informal communication was presented by B. S. Butler on Basic 

 ferric sulfates in Utah. 



REGULAR PROGRAM 



A remarkable skeleton of Stegosaurus (illustrated) : C. W. Gilmore. 

 The type specimen of Stegosaurus stenops recently prepared and placed 

 on exhibition in the U. S. National Museum constitutes the most per- 

 fect skeleton of this remarkable chnosaur ever found. It is also unique 

 in being the first specimen to give positive evidence as to the position 

 and arrangement of the large dermal plates with which, in life, its back 

 was adorned. The position of the various parts of the skeleton, as ex- 

 plaining the manner of death, and entombment of this particular speci- 

 men were discussed. 



The facts relating to the dermal armor which now appear to be es- 

 tablished from this preliminary study are: (1) That the armor of the 

 neck, back, and tail was formed by two rows of erect plates, the ele- 

 ments of one row alternating with those of the other; (2) that the total 

 number of plates in the two rows was not less than 20 and not more 

 than 22; (3) that the position of the largest plate of the series appears 

 to be above the base of the tail and not over the pelvis; (4) that the 

 usual number of dermal spines on the tail is four arranged in two pairs. 



