19 



curved, (or perhaps sometimes rigid) proceeding rectangularly 

 from the main stipe : which is celluliferous on one side (per- 

 haps on both sides.) Branches plain and linear, celluliferous ? 

 Substance corneous brown or black in the shale and limestone. 

 The cellules on the central stipe are round or oval, and 

 there are some obscure indications of cellules on the branches, 

 but their determination is very unsatisfactory. 



BUTHOGRAPTUS laxus, (n. s.) 



Description. Frond slender, lax and flexuous, midrib or 

 stipe linear, with oval spots marking the form and place of 

 the cellules. Branches coming off at right angles to the stipe, 

 slightly recurved in the middle, and sometimes bent abruptly 

 backwards. Some obscure markings upon the surface of the 

 branches may indicate the place of cellules : branches with 

 lanceolate terminations. Surface striated. 



Geological Formation and Locality. In dark-colored shaly 

 Emestone of the age of the Trenton limestone; at Platteville 

 and vicinity, Wisconsin. 



MELOCRINITES nodosus, (n. s.) 



Description. Body pyriform, base truncate, gradually ex- 

 panding to the top of the radial plates; dome rounded and 

 more or less convex. Basal plates four, strongly nodose, ex- 

 tended laterally, and ore half or more of the entire width 

 occupied by the articulating facet of the column, which is 

 deeply inserted. Radial plates three; the first largest and 

 heptagonal; the second smaller and hexagonal; the third hep- 

 tagonal. Interradial plates in series of one, two, and three: 

 the first hexagonal and as large as the second radial; the 

 second hexagonal and a little smaller than the third radials; 

 the third smaller and somewhat irregular. The oval sido is 

 not usually distinguishable from the others, unless it be some- 

 times in a series of two larger plates above the second range 

 in the interradial area. The dome consists of numerous small 

 polygonal plates with a central or sub-central aperture or 

 proboscis. 



The third radial is a bifurcating plate, and upon the upper 

 sloping sides re3t brachial plates ; of which there are two or 

 three ranges below the free arms. Arms two from each ray, 

 the structure unknown. The surface is' marked by strong 

 rounded tubercles, a single one on each plate, which, at its 

 base, occupies the greater part of the area of the plate. These 

 nodes are sometimes much elongated and smoothly rounded at 



