348 
POPULAR SCIENCE REVIEW. 
ture of serpentine and carbonate of lime. In general a sheet of pure 
dark-green serpentine invests each mass of pyroxene, the thickness of the 
serpentine varying from the sixteenth of an inch to several inches, rarely 
exceeding half a foot. This is followed in different spots by parallel, waving, 
irregularly alternating plates of carbonate of lime and serpentine, which 
become gradually finer as they recede from the pyroxene, and occasionally 
occupy a total thickness of five or six inches. These portions constitute the 
unbroken fossil, which may sometimes spread over an area of about a square 
foot, or perhaps more. . . . 
The general character of the rock connected with the fossil produces the 
impression that it is a great Foraminiferal reef, in which the pyroxenic 
masses represent a more ancient portion, which having died, and having 
become much broken up and much worn into cavities and deep recesses, 
afforded a seat for a new growth of Foraminifera, represented by the 
calcareo-serpentinous part. This in its turn became broken up, leaving in 
some places uninjured portions of the general form. The main difference 
between this Foraminiferal reef and more recent Coral-reef seems to be that, 
while with the latter are usually associated many shells and other organic 
remains, in the more ancient one the only remains yet found are those of the 
animal which built the reef. 
Dr. Dawson^s masterly exposition of the peculiar appear- 
ances seen under the microscope in the alternating calcareous 
and serpentinous laminae in this peculiar marble, and of the 
relation of the first to a Foraminiferal many-chambered shell,, 
such as still exist, and of the second to its segmented jelly- 
flesh (or sarcode) converted into a green sihcated mineral, was 
based on a rigorous examination (with the light of CarpenteFs 
Researches on Foraminifera of thin slices or films of the 
marble, and substantiated far more easily by the production 
of the silicated segments of sarcode and their connecting 
threads, by the removal of the calcareous or shelly matter by 
acid. Dr. Carpenter has not only had the pleasure of verifying 
(at Sir W. Logan^s request, and with specimens supplied by 
him, op. cit., p. 59) Dr. Dawson^s conclusions, but of even 
adding to his almost exhaustive account of the structure of 
this curious fossil. 
Our readers will already have been grounded in a knowledge 
of Foraminifera, their shells, their flesh or sarcode, their 
pseudopodia or threads of sarcode protruded through the shell, 
their mode of growth, habits, and place in the animal king- 
dom, by Professor Williamson^ s illustrated memoir in No. XIY. 
of this Review (p. 171, pi. 8) ; for further details they must 
go to CarpenteFs ‘"‘’Introduction to the Study of Forami- 
nifera,-’'’ published by the Ray Society. It is sufficient here 
to state that a simple round atom of the living gelatinous 
matter, or sarcode, invested with an exquisitely thin shell of 
carbonate of lime, may be said to constitute a Foraminifer 
