1878. ] Microscopical Examination of Rocks. 219 
Epicauta and Meloé, is not conspicuous, and in this respect, as 
well as in the final transformations taking place within the two 
unrent skins, the insect approaches Sitaris. In the hairless and 
unarmed surface of the second larva, and of the third larva and 
pupa, as shown by careful examination of their shrunken exuviz, 
the insect also resembles that genus. 
[To be continued in May Number] 
EE Pee Seg MORES ee Re Rp ry AP 
een Sy 
THE PREPARATION OF ROCKS AND FOSSILS FOR 
MICROSCOPICAL EXAMINATION. 
BY R. FRITZ-GAERTNER, PH.D. 
T is often supposed by those who have never prepared sections 
of rocks or fossils that the process is associated with great 
difficulties and expenditure of time, but this in reality is not the 
case. A small amount of practice is needed for the beginner and 
he may soon be able to manufacture sections which are fit for the 
microscope.. The time spent in the mechanical operation of 
grinding rocks is not only remunerated by interesting and 
_ instructive preparations, but adds also to a complete knowledge 
= of their physical structure, gained by a close observation of the 
various features they present during the process of preparation. 
In cases where large numbers of sections are to be prepared 
= itis not possible for the lithologist or paleontologist for want of 
_ time to perform all the work himself: he may be assisted by any 
person of ordinary ability in the preliminary part of preparation. 
= Those who do not personally wish to prepare sections can be 
: - referred to Mr. Fues, of Berlin, or to Mr. A. Julien, School of 
_ Mines, New York city, who prepare and deal in sections, which, 
= On account of their perfection, deserve commendation. 
= In the present article I wish to describe the process of pre- 
_ paring rocks or fossils for microscopical study. They are mainly 
intended for those who design to make sections themselves, and 
to whom a detailed description of a mechanical operation may be 
of some assistance in their first attempts. 
_ Selection of Rock Material—It is quite important in order to 
make a complete microlithological analysis of rocks to select 
material which is characteristic. Most rocks are in various states 
VOL. X41.-—-NO. IV. 16 
RRS ER A E eS Nt ey Pe A RENE ANS Me Ad ea LenS PE ELL My OMe oer es eee ST SL A 
SoTL Og TNS aj i PENEN dhe 
er ae Ree or, 
