he, Dip 
MICROSCOPICAL EXAMINATION. 6 
Cr 
rose and apple, the original was dicotyledonous (Plate I7J, 
Jigs. 4, 8). 
Leaves of a large size, destitute of veins, and irregularly 
divided, probably belong to fuci, or other marine plants 
(Lign. 10). 
Such are the rules for the investigation and interpretation 
of the characters of stems and foliage, which have been 
preserved by mineralization. Their application is not diffi- 
cult, and the student may by their assistance obtain some 
general indications as to the nature of the original trees or 
plants, whose petrified remains form the subject of his exami- 
nation. 
ON THE MICROSCOPICAL EXAMINATION OF FOSSIL VEGETABLES. 
Mr. Nicol, who first suggested the method now generally 
- adopted for preparing eacil wood, coal, &e. for microscopical 
examination, and which was employed by Mr. Witham in 
the illustrations of his beautiful work on the structure of 
fossil plants,* has so clearly explained the process, that by a 
little practice the student will be able to prepare specimens 
sufficiently thin for every useful purpose. Several lapidaries 
in London, (see list at the end of this work,) polish and 
mount fossil vegetables and other substances, in a very supe- 
rior manner ; but their charges are high, and they frequently 
injure specimens by grinding them too thin, and thus obli- 
terating structure. I would recommend that a small chip 
of the specimen, if possible in a radial direction, should be 
examined by reflected light, always beginning with the 
lowest object-glass and eye-piece, and ascending to the 
highest power ; at first without any preparation ;t+ subse- 
quently the object should be immersed in oil of turpentine, 
* Observations on Fossil Vegetables. 4to. 1833. 
+ The drawings in Plate V. figs. 2 and 3, of fossil coniferous wood, 
were from chips seen by reflected light, and without any preparation. 
VOL. I. F 
