CALCISPHERA. 107 
It corresponds with the lower brown division of Mr. G. H. 
Morton, F.G.S. The place at which I first observed it, 
and where it is best seen, is the Ty-nant ravine, two miles from 
Llangollen. 
The rock in which Calcisphera is most abundant is a very 
pure fine grained limestone, having a clean fracture, and in 
colour varying from light to dark brown. Scarcely any other 
form of life than microscopic is present. Calcisphewra occurs so 
freely in some bands, that it may be said to form the lime- 
stone. Foraminifera are also distributed throughout these 
lower beds. These facts would seem to point to a quiet deep 
sea deposit of moderate depth. 
I must not omit to notice the presence of minute crystals, of 
quartz, which occur in varying proportion, but are present in 
the purest stone. The only form of life, other than microscopic, 
which I have seen associated with Calcisphera, is Euomphalas 
sp. and Murchisonia sp. In the shales, between the bands of 
limestone, fossils are more abundant, and include the rare 
Producta Llangollensis, and Leperditia, &c. 
I have found by chemical analysis that the purer the lime- 
stone, the more abundant is Calcisphera. Selected pieces of 
the stone, full of Cadcisphera, yielded over 99 per cent. of Calcic 
and Magnesic carbonate. 
I append an analysis, by GEORGE SHRUBSOLE of the Etruria 
Laboratory, Hanley, of a typical piece of the limestone. The 
stone from which fragments were taken for analysis will be 
found in the Museum, with a polished surface to shew the 
Calcisphera. 
Carbonate of Lime es ue ww .. 97°14 
Carbonate of Magnesia .. ts; *e wets. E85 
Silica and Silicate of Iron ade tne hs "47 
Tron Oxide and Alumina re oa ba 35 
Organic matter .. oe ee a +. ‘or 
Moisture .. Lv ee ac g ue *28 
Phosphoric Acid .. os ee in ..” traces 
In bringing this subject forward, my primary object has been 
to indicate where the limestone containing these remarkable 
organisms is to be found, and the conditions under which they 
occur; points which have some relevance in determining their 
morphological character, and also to offer a few suggestions in 
defence of the Radiolarian origin of some at least of these 
organisms. 
In naming these organisms Calcisphera, PRor. WILLIAMSON 
says that he does so ‘as not involving any premature 
hypothesis respecting their nature.” As to what they really 
are, he tells us “they are wholly unlike any living organism 
that we are acquainted with. The spherical form suggests the 
