34 
beds formerly called Portlandian are now classed with 
the Kimmeridge group. The two specimens now exhibited 
were found in the Coral rag of North Crimston, near 
Malton. Unfortunately this species is very rare, and the loop 
has not yet been examined. The external form of the beak, 
small foramen, sharp beak ridges, and the deltidium in two pieces 
would indicate that this species belongs to the genus Waldheimia 
or the sub-genus Zeilleria, which was formed to contain those 
long looped species that are smooth and without plications. 
More specimens may be found which will permit the loop to be 
examined, or will show the dark line on the smaller valve 
indicating the presence of a septum, and therefore of a long loop. 
Since this paper was read, a third specimen has been found by 
Mr. Chadwick, which he kindly presented to me. The locality 
was Langton Wold pit. 
J. F. WALKER. 
NOTE ON SOME CRYSTALS OF CELESTINE. 
Last year, Mr. J. Collins, of Coventry, presented the Society 
with two crystals of Celestine found in the bed of the River 
Nidd, near Knaresborough. This mode of occurrence, though 
by no means unprecedented, is somewhat unusual for Celestine : 
it is common in the case of Barytes, and very common in the 
case of Grypsum. The crystals in question are small (about %" 
long), of light blue colour, and have rough irregular faces 
bearing impressions of other crystals which have grown in con¬ 
tact with them and have subsequently been detached. They are 
simple in structure, the only forms present being 001, 110, 012, 
and 101 (op, ocp, 4 poo, poo). Miller’s combination o c c/ 
The faces of 101 are straited parallel to their intersections with 
111. A somewhat curious point is the existence of faint 
cleavage 012. 
H. M. PLATNAUER. 
