424 University of Kansas Geological Survey. 



the entire surface. Size variable, but on the whole much larger 

 than that of G. bulloides, the diameter being two or three times 

 greater. Lack of any description of such a form has led to the 

 provisional application of the term spinosa to the species. It is 

 very common, appearing abundantly in the Fort Hays of the 

 Niobrara, and in the Lincoln marble of the Lower Benton. The 

 specimens are well preserved and quite distinctly apparent in 

 the sections, with all the details of structure exhibited. 



Coccoliths and UliabdolitJts. (PI. lxxxv, f. 10.) 



Mention has several times been made concerning the cocco- 

 liths and rhabdoliths found in the different rocks. These curious 

 and puzzling forms constitute a large part of the real chalk, and 

 become plainly visible in properly prepared specimens. In the 

 beginning it may be stated that nothing new was learned re- 

 garding the true character of these organisms, if such they are. 

 Reference to the figure (pi. lxxxv, f. 10) will show, however, 

 that the usual conception of simplicity of structure is hardly 

 sufficient in the way of explanation. 



The Coccoliths were observed in some six or eight different 

 varieties, but they offered no variation in connection with their 

 derivation from different localities. The "cup and saucer" 

 form, described as so characteristic of the recent specimens, was 

 not observed at all. On the contrary, the elementary form 

 seems to be a ring, circular or oval, spanned by two bars, either 

 at right angles to each other or sometimes at a greater angle in 

 the oval variety. Frequently only one bar is present, and at 

 other times three cross the center of the disc. That these are 

 true projections, is shown by the fact that remnants of them 

 remain attached to fragments of the rim in broken specimens. 

 Occasionally, in entire forms, the bridging rods are represented 

 by imperfect septa of irregular contour that do not reach the 

 entire distance across the space inclosed by the rim. Less fre- 

 quent modifications are those in which the rim incloses a solid 

 center, which may be merely granular or be perforated by 

 numerous small, round openings. 



The peripheral rim, in the majority of cases, is merely a sim- 



