ART. 15 THE FOSSIL CRINOID GENUS VASOCRINUS KIEK 13 



Very little of its structure can be made out. It was originally buried 

 in a very hard fine-grained limestone, and great difficulty was had 

 removing the closely adherent matrix. 



The highly developed knifelike keels or carinae that form the 

 characteristic ornamentation of the species and the character on 

 which Lyon based his name are very interesting. In the type speci- 

 men, which is a fairly young individual, these ridges are worn down 

 and show as slits, proving that at least in their basal portions the 

 carinae are sharp folds in the thin plates. Dissociated plates and 

 interiors also show this fact clearly. The higher portions of the 

 carinae are solid. 



Tlorlzon and localities. — Lyon writes that his specimens were col- 

 lected " about 5 feet beneath the Devonian black slate, and above 

 the beds of Hydraulic cement stone, Jefferson County, and in the 

 same geological position on the falls of the Ohio." This w^ould place 

 the species in the Beechwood limestone member of the Sellersburg 

 limestone (approximately Hamilton). One lot of material bears a 

 recent label of " Falls of the Ohio, Clark Co., Ind." Another 

 silicified specimen with the infrabasals practically worn away but 

 otherwise in an excellent state of preservation was collected by 

 H. Hertzer in the State quarries at Columbus, Ohio. The horizon 

 is stated to be Onondaga, but it is more probable that the speci- 

 men was collected from the Delaware limestone, of Hamilton and 

 Marcellus age. 



VASOCRINUS TURBINATUS. new species 



In the Springer collection is a single theca of Vasocrlnus labeled as 

 coming from Louisville, Ky. The specimen is in a splendid state of 

 preservation, the entire cup and the greater part of the tegmen being 

 shown in great detail. It is unfortunate that the specimen can not 

 be referred to V. valens, but its close relationship to that species per- 

 mits the structures shown to be added to those of V. valens with the 

 utmost confidence. 



Following are measurements of the tj^pe and only known specimen : 



Height of dorsal cup, 15 mm. 



Diameter of dor.sal cup (aut. R. to Post. IR), 1G.5 mm. 



Diameter of stem, 5.4 mm. 



Height of IBB, 2.6 mm. 



Height of BB, 5.8 mm. 



Breadth of BB (average), 6.3 mm. 



Height of RR (average), 4.1 mm. 



Breadth of RR (average), 7 mm. 



Breadth of arm facet (average), 4.5 mm. 



As will be noted from the measurements, the height and breadth of 

 tlie dorsal cup are approximately equal. In form the cup is sub- 



