\Pi oceeding s Belfast N % t uvci lists' Field Club. — Appendix 1885-1886.) 
A LIST OF THE CRETACEOUS FORAMINTFERA OF 
READY HILL, COUNTY DERRY. 
BY JOSEPH WRIGHT, P.G.S. 
— $— 
the year 1874 I published a List of the Cretaceous Microzoa of Ireland. 
U|\ It was the result of three years’ exploration in the chalk of the Counties 
of Antrim, Derry, and Down, the only counties in Ireland where rocks of 
this age occur. The Greensand in Ireland appears to he almost devoid of 
Microzoa. Only two Foraminifers have as yet been found in it— viz., Orbito- 
lina concava * and Cristellaria rotulataf I have on one or two occasions 
examined greensand rocks under the microscope, but failed to find any trace of 
these organisms in them. With the above two exceptions, all the Microzoa 
found in the Irish Cretaceous rocks have been obtained from a mealy powder, 
known as chalk powder, which is of frequent occurrence in cavities in the 
flints. I do not remember to have ever visited a chalk exposure with flints 
that did not yield, on searching, at least some of this powder. At some places 
it was very scarce, at others it was abundant. It may have been merely acci- 
dental, but flints found in the vicinity of the sea usually contain a much greater 
quantity of the powder than those found farther inland. 
The chalk in Ireland is a hard, compact limestone, known as white “ lime- 
stone,” of the same age as the soft white chalk of the South of England, but 
very different in character, the hardness of the Irish stone being presumably 
due to the heat and pressure of the overlying basalt. The flints foimd in it are 
* Tate, Cretaceous Rocks of Ireland, Quart. Journ., Geol. Soc., 1865. 
+ Wright, Cretaceous Microzoa of Ireland, Rep. andProc., Belfast Nat. Field Club, 1874, 
a PP» P» 73, 
