288 Whiteaves — Uintacrinus and Hemiaster. 



satisfactorily distinguished from some forms of the typical and 

 very variable U. socialis. 



In Utah and Kansas Uintacrinus is said to have been found 

 only in the Niobrara chalk, but the exact equivalent of that 

 subdivision of the Upper Missouri section has not yet been 

 recognized in the Nanaimo group of the Vancouver Creta- 

 ceous. The specimens of Uintacrinus from Vancouver and 

 Salt Spring islands are from the lower beds of the Nanaimo 

 group, below the coal, and it has yet to be ascertained whether 

 the genus occurs at a little higher geological horizon than the 

 Niobrara at those islands, or whether the supposed lower beds 

 of the Nanaimo group may not at some places represent or 

 include the Niobrara. In "the Queen Charlotte Islands the 

 " Upper shales and sandstones, or subdivision A, of Dr. G. M, 

 Dawson's Report" on these islands, which hold Inoceramus 

 labiatus (problematicus) are supposed to represent the Nio- 

 brara. 



The spatangoids are casts of the interior of the test of a 

 species of Hemiaster, from shales and sandstones of the 

 Nanaimo group, at four localities on Vancouver Island and one 

 on Salt Spring Island. Many of these casts are distorted and 

 crushed out of shape, but others are well preserved and very 

 little if at all distorted. Two of them, in particular, are 

 almost perfect and very well preserved, and both of these have 

 recently been presented to the Museum of the Canadian Geo- 

 logical Survey. One of them, the first that was obtained, was 

 found by Miss Wilson, in 1897, on the north bank of the 

 Cowichan River, V. I., near Menzies Creek ; and the other by 

 Mr. Harvey, in 1903, at Shopland, V. I. Mr. Harvey writes 

 that he has found specimens of this heart urchin all over the 

 Cowichan coal-field, V. I., at the northeast end of Salt Spring 

 Island, and at Crofton, V. L, the most southerly point of the 

 Nanaimo coal-field, in 1902, 1903 and 1904. 



Only one species of Hemiaster has previously been recorded 

 as occurring in the Cretaceous rocks of North America. This 

 is the H Humphrey sanus, from the Fort Pierre or Montana 

 formation of the tipper Missouri country, and district of 

 Athabaska, which was first described by Meek and Hayden in 

 1857, and re-described and figured by Meek in 1876. But the 

 fauna of the Cretaceous rocks of the Pacific coast is in many 

 respects different to that of their representatives in the great 

 interior plateau, and the Vancouver Hemiaster seems to differ 

 from H. Humphrey sanus in its much more depressed and 

 widely suboval or subovate form. It may be provisionally 

 named and described as follows : 



