19 



This shale well repays careful study, for in it occur a large 

 number of those minute problematical bodies, the " Cono- 

 donts." The\ r are readily detected by the use of a lens, and 

 from the nature of the rock in which they are imbedded, 

 they are in an excellent state of preservation, and afford 

 interesting objects for microscopic stud} r . 



Ambocoelia praettmbona (Hall) occurs in considerable 

 numbers in some portions of this shale, but the specimens 

 are smaller on the average than those found in the cal- 

 careous bed above. Liorhvnchus multicostus (Hall) also 

 occurs, the specimens occasionally attaining great size. 

 Some of the specimens of this species from these shales, 

 approach much more closely to the typical L. quadricostatus 

 ( Vanuxem ) of the Genesee than any of those found either 

 above or below. Besides these, the minute pteropod Stylio- 

 lina fissurella (Hall) occurs, often in considerable numbers, 

 on the laminae of the shale. 



Section 2(G). 



Plate V. 



This section is a very short one, being scarcely more than 

 three hundred and fifty feet in length. It is cut in the left 

 bank of the stream, and extends in the same general direc- 

 tion as the preceding one. The dip of the strata is greater 

 than that of Section 1, being about 2.5 degrees to the south- 

 east. A large portion of this section is covered by the de- 

 composed shale which the rains have carried down from 

 above, and on -which a strong growth of vegetation has 

 become established, obscuring the rocks underneath. In 

 consequence of this, the upper strata are well exposed only 

 near the up-stream end of the section, but from the steepness 

 of the bank at this point the study of these strata is 

 attended with considerable difficulty. 



The Black Naples Shales appear at the top of this section, 

 and they are again exposed in a "dug way" which leads 

 from the terrace, just beyond the section, to the top of the 



