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DE. W. B. CARPENTER AND ME. H. B. BEADY ON 
bably due to other causes rather than to the size of the constituent sand-grains, and 
chiefly to two, viz. a slight difference in the character of the sub crystalline deposit in the 
chambers, and the partial disintegration of the shell-structure from pressure or other dis- 
turbing cause, during, or it may be previous to, the process of mineralization. I have 
noticed that, the specimens in which the exposed portions are the roughest and most 
granular, are those in which the structure is most contused, not merely in the labyrin- 
thic growths, which are naturally of coarser texture, but even in the compactly built 
spiral lamina, which, usually so well defined, is often scarcely traceable in such indi- 
viduals. 
46. It has been stated that the shells of a number of the minuter forms of Foraminifera 
are to be found imbedded in the shelly material forming the test, their presence being 
due to the fact of their having been living amongst the sand in the neighbourhood of 
the animal whilst the process of building its skeleton was being carried on. Their 
identification is of considerable importance, as they afford, together with the organisms 
to be observed in the limestone matrix, the only data by which the depth of water wherein 
the animal lived, may be indicated with any degree of accuracy. In the test itself the 
following have been noticed : in many cases it is impossible to do more than identify the 
Genus, specific and varietal characters often depending on peculiarities not to be recog- 
nized in sections. 
Biloculina ringens , Lamk. 
Biloculina contrariety D’Orb. 
Triloculina oblong a, Montagu. 
Triloculina trigonula , Lamk. 
Triloculina tricarinata , D’Orb. 
Quingueloculina seminulu/m , Linn. 
Spiroloculina jilanulata, D’Orb. 
Trochammina incerta , D’Orb. 
Planularia longa , Cornuel. 
Textularia sagittula , Defrance. 
Textularia variabilis, Will. 
Textularia pygmcea, D ’ Orb . 
Bigenerina nodosaria, D’Orb. 
Biscorbina, sp. 
Botalia Beccarii , Linn. 
The specimens seen in the limestone rock are generally of much larger size than those 
which have been built into the walls of Loftusia itself. Most of the foregoing varieties 
occur, and, in addition, the following, — 
Spiroloculina canaliculata , Czjzek. 
Valvulina Austriaca, D’Orb. 
Gristellaria , sp. 
Dentalina , sp. 
Bulimina ovata, D’Orb.. 
Planorbulinct ammonoides, D’Orb. 
Botalia Schrceteriana, P. & J. 
Nummulina , sp. 
The last named is one of the small thick forms characteristic of the lower Tertiary 
strata. 
47. Mr. W. K. Parker has given me much assistance in these determinations. The 
conclusions to be derived from them are that the rock is a lower Tertiary limestone, very 
similar to some of our Miliolite limestones, but richer in the small arenaceous forms ; 
