THE 



GEOLOGICAL MAGAZINE, 



NEW SERIES. DECADE III. VOL. IV. 



No. XII.— DECEMBER, 1887. 



oie,xc3-iifT.A.ij JLiaarioxjiss. 



I. — On a New Specimen of Sol aster Murcbisoni frobi the 

 Yorkshire Lias. 



By Prof. J. F. Blake, M.A., F.G.S. 



(PLATE XV.) 



THE specimen to which, the following description applies was 

 found by the Eev. G. Crewdson, F.G.S. , of Kendal, at the base 

 of the cliff at Huntcliif. The block in which it lay was separated 

 from the parent rock, and had doubtless fallen from above. The 

 occurrence in the same slab of a portion of an arm of OpTiioderma 

 Milleri and the general character of the stone leave no doubt that it 

 is derived from the " Star-fish " bed of the Capricornus Zone. 



The only other known examples of polyradial star-fish from the 

 Yorkshire or any other Lias are figured on plate v. of Dr. Wright's 

 Monograph of Oolitic Asteroidea in the Palceontographical Society's 

 volume for 1861, issued in 1863. These are named Plumaster 

 ophiuroides, and Luidia Murchisoni respectively. That our fossil is 

 not the same as the former is very evident from its possessing 22 arms 

 instead of 14, and other differences are soon observed. On com- 

 parison with the latter, as represented by its figure and description, 

 it appears very closely allied; but this is described as a Luidia. 

 The principal difierence between a Luidia and a Solaster, that can 

 be observed on such examples, is that in Luidia the ventral surface 

 of the arms has one medial row of ossicles, with the pores on either 

 side, whereas! in Solaster there are a pair : a circumstance that 

 results in dried sjaecimens of the latter opening along the ventral 

 side of the rays, while in the former the rays remain intact. Now, 

 on examination of our specimen, it is immediately evident that in 

 this respect it agrees with Solaster. Therefore, if the specimen 

 described by Dr. Wright is a Luidia, this cannot be the same. This 

 was my opinion when I exhibited the specimen at the British 

 Association at Manchester in September last. But on that occasion 

 Prof. Williamson, who found the specimen figured by Dr. Wright, 

 and also provided the description, considered the new specimen so 

 like the old, that a comparison became necessary. Through the 

 kindness of Mr. J. Woodall, I have been enabled to examine the 

 other specimen in the Scarborough Museum, as it was found to be 

 in too fragile a condition for safe carriage. The result of that 



DECADE III. — VOL. IT. — NO. XII. 34 



