722 J. HOWARD WILSON 



extend upward into this so-called "fragment bed," in the form of 

 streaks and pockets, appearing less and less in the upper part. 



The proportion of shell material to sand in No. 15, as compared 

 with Nos. 12, 13, and 14, taken as one bed, was found to be con- 

 siderably less. This would be expected in the resorting of material, 

 the lighter and more soluble shell material being dissolved and borne 

 away, leaving a greater proportion of sand. No. 15, then, has all 



** ■ ■:- ■■•■ *L_ 



Fig. S 



the appearance of being a disturbed and partially assorted portion 

 of the "upper shell bed." 



In exposing these beds northward along the bluff, it was found 

 that at a distance of 25 or 30 feet from the section, No. 15 pinches 

 out, while the three beds below have become indistinguishable and 

 their combined thickness is only 9 inches. No. 11 also appeared 

 finer and less shelly, and had increased in thickness to 1 foot, 6 inches. 

 The most noteworthy fact, however, and that which is responsible 

 for the thinning out of these upper beds, is the unconformity of 



