Notice of New Localities of Sahlite, Coccolite, &c. 91 
where the clusters were, and apparently were not attached 
to any rock. It was not uncommon to find, on breaking 
the larger crystals, small lumps of oxide of iron and specks 
of mica within them, and in some cases six sided crystals of 
mica enter the sides of the augite crystals. Of the number 
of these no estimation can be formed. ‘There are thousands 
about the size of the finger and myriads of those which are 
smaller. The positions of the clusters are very variable. 
As has been remarked, some are on the corners, some on 
the edges, and some on the surfaces of the fragments. 
Others lie in nests like geodes within the surface, and oth- 
ers fill the sides and bottom of deep channels, passing quite 
round the mass to which they adhere, and in some cases 
they cover it so thickly in little groups as to render it diffi- 
cult to handle the specimens without breaking off small 
ones. Inthe cavities just spoken of, frequently lie lumps of 
carb. lime fastened in by crystals which enter them in various 
directions. The crystals are grouped together in numberless 
fantastic modes, intersecting, lying on and passing through 
each other at all angles, usually without producing any 
alteration in their respective forms. When, however, one 
passes across the truncated edge of another, an alteration in 
the depth of the truncation is often the consequence. From 
a similar cause, and sometimes without any apparent one, a 
very different and singular appearance is exhibited—reenter- 
ing angles. 'These appear sometimes instead of a truncation 
and sometimes in the middle ofone. In both these instances 
the faces containing the reentering angle are parallel to the 
sides of the primitive parallelopiped. Occasionally such an 
angle very obtuse, is produced by a truncation’s passing 
only part of the way across-the edge, when of course the 
angle is contained by one face of the primitive and the face 
forming the partial truncation. It is not often that more 
than one of these angles is found on a crystal; occasionally 
two, which are generally on opposite edges of the primitive, 
though I have found one or two where they occurred on 
adjacent ones. A perfect notion of all these cases will be 
conveyed by sections parallel to the base. See figures, (1.) 
(2.) (3.) (4.) (5.) See plate If. Crystals of the form indi- 
cated by fig. 2, occur more frequently than the others. It 
has eleven faces. Fig. 3, shows one with fourteen. The 
terminations of these crystals are like those which are eight 
