28 BULLEIIN OF THE LABORATORIES 



may have to the disinterested generosity of his distinguished friend. 

 Equally indispensible has been the work uf friendly collectors, Mr. 

 W. F. Cooper having assisted most largely, while Messrs. C. J. Her- 

 rick, Ira Crawford, E. S. Clarke, J. L. Deming, and many other stu- 

 dents and friends have similarly assisted. 



The tabular review is intended to exhibit at a glance the general 

 stratigraphical conditions as well as certain comparisons bearing on the 

 age of the group. It will be constantly remembered that only a part 

 of the species collected are described in this number. 



I. signifies all below conglomerate I, as seen at the foot of the 

 south Newark quarries; II. is that section including the freestone at 

 Newark and ending with conglomerate II, ^o feet above the base of 

 the quarries at Newark; III. is the remainder of the s ries including 

 shales and fl igs to the base of the Chester or coal-measure conglom- 

 erate as the case may be. 



Phillipsia mzraTneceiisis, Shumard. 

 (Plate XI, Fig. 3.) 



A single pigidium from near the top of the Waverly east of Rush- 

 ville. 



Pigidium considerably wider than long, parabolic in outline, 

 with a very narrow border; axial lobe broad and high, fully 

 Yz as wide as the pigidium proximally, composed of thirteen narrow, 

 unsculptured segments, prominently truncate behind, separated from 

 the pleur?e by a not very deeply impressed sulcus, but rising above 

 them almost at once ; pleurae rather convex, eight segments being evi- 

 dent, which are low and flat, with a slight groove on the top of the 

 first and second near the posterior edge ; the narrow border of uniform 

 width and abruptly deflected. Length 8 mm; width 11 mm; width 

 of axial lobe 7 mm. 



The figures given by Shumard do not show the characters empha- 

 sised in his description, which agrees quite fully with our specimen. 

 The species was originaly found in the Archimedes limestone at Fen- 

 ton, St. Louis Co.. Missouri, a horizon, apparently the equivalent of 

 the one here noted. 



