MIOCENE BEDS OF THE MALTESE ISLANDS. 521 
that there was apparently no distinction to be made between them 
and detached fragments of the parent-rock or of the Lower Limestone, 
as the case might be. They had the aspect of having been washed 
and worn by marine action, and contained the fossils of the bed 
and many forms not found in it. 
The greatest thickness of the calcareous sandstone may be a little 
over 200 feet. 
Besides the nodule seams, interspersed throughout the bed are 
dense bands and nodules of chert, of a grey-brown colour and con- 
choidal fracture. These may take the shape of rounded masses, but 
are oftener seen forming thin seams in a pale-coloured sandstone 
towards the base of the bed. Concretionary nodules of red heema- 
tite and clay-ironstone are also met with throughout the bed, but 
in greatest abundance in the upper parts near to the marl; also in 
the same situation nodules of crystallized gypsum appear, even 
below the first nodule seam, where lumps of iron-pyrites, with 
sulphur in small quantities, are met with as in the overlying marl. 
The Vertebrata will be noticed in the sequel. 
The invertebrate fauna of the Caleareous Sandstone and the 
nodule seams are conspicuously represented by Pecten and Kchinida, 
Pecten cristatus, Bronn?, P. scabellus, and P. squamulosus being 
plentiful. Clavagella and from 2 to 3 species of Scalaria, and 
Spondylus, Ostrea Boblayei, and O. Virleti are common, besides 
numerous other species *. 
Out of 21 forms met with in the Marl, about 12 affect also the 
Calcareous Sandstone and its nodule bands. 
The Brachiopoda are Terebratula sinuosa, T. minor, Terebratulina 
caput-serpentis, and Thecidium Adamsi, the first being the only one 
common also to the marl. 
Of 22 species of Echinodermata found in the Calcareous Sandstone, 
9 are common to it and the Upper Limestone, whilst 4 are also 
common to the Sand bed, and 2 are also found in the Marl. 
Foraminifera in this bed are noticed Geol. Mag. vol. in. p. 152. 
V. The Lowrr Limestone has its upper horizon marked by what 
I have named the “ Transition or Scwtella-bed” t. 
The upper portion of this stratum passes so imperceptibly into 
the Calcareous Sandstone that, were it not for certain organic remains 
which constantly mark the point of transition, it would be difficult 
to define where the one ends and the other begins. 
The saucer-shaped Scutella subrotunda and the Orbitoides Man- 
telli t congregate in the above situation in great abundance. 
The Lower Limestone presents considerable variability. It may 
be concretionary and oolitic in its composition, or irregularly com- 
pact and often semicrystalline. Large portions are made up of 
broken shells, Corallines and Foraminifera, whilst the structure of 
much of the upper parts is made of globular white nodules, strewn 
irregularly throughout a lamellar or concentric bedding. 
The colour varies from a pure white to a cream-colour. 
* Author, op. cit. p. 129; Forbes, Proc. Geol. Soe. iv. p. 280. 
t Op. cit. p. 138. t Geol. Mag. vol. i. p. 104, and vol. ii. p. 152. 
