136 PROCEEDINGS OF THE ACADEMY OF [1888. 



Plumulites gracilissimus, (n. sp.) PL VII, fig. 8. 



Plate exceedingly frail and delicate. Phylliforni base broad, 

 evenly tapering to an acute apex, curved laterally, one margin 

 slightly concave or nearly straight, the other quite convex ; this lat- 

 ter side is considerably shorter than the other, thus giving an up- 

 Avard slope to the base towards this side. Surface ornamented by a 

 median narrow ridge which follows the same general curve as the 

 plate and tapers to a point at the apex. On the longer half of the 

 plate, as divided by the median elevation, there is a secondary fili- 

 form ridge or striation subdividing that portion into two equal halves ; 

 it extends from the base upwards towards the apical end, finally be- 

 coming lost before reaching it. 



These two longitudinal cariuse are crossed by twelve or more 

 transverse lines which curve downwards in the centre from the two 

 sides towards, and having the same contour as, the margin of the 

 base ; they are equi-distant and are placed about as fixr apart as the 

 width of the central elevation. Length six millimeters. 



This species approaches P. mininius Barr., in size, but is more elon- 

 gate like P. delicatus Barr., from which it differs in having a nar- 

 rower central elevation. Its fine lateral striation which again sub- 

 divides the longer lateral half is quite distinctive. 



From the lower third of the shale at Lockport only separate plates 

 have as yet been found. 



Explanation of Plate VII. 



Fig. 1. Buthotrepis gregaria, n. sp. One individual from the type 



slab. 

 Fig. 2. Inocaiilis anastomotica, n. sp. Portion of the type frond. 

 a. Terminal of a branch from another portion of the 



frond enlarged. 

 Fig. 3. Dendrocrinus celsus, n. sp. Specimen with only a portion 



of the column represented. 



a. Fusiform enlargement observed near the centre of 

 the column. 



b. Portion of column near root. 



c. Root. 



Fig. 4. Mariacrinus ivarreni, n. sp. Calyx with a portion of the 

 column; the rest has been omitted, except: — 



a. The portion at its termination sho^ving its peculiar 

 spiral ending. 



