62 Introduction to Geolozy. 
frequently called “naked ladies.” This small order produces 
nothing of extraordinary importance. ‘The fourth order, 
Hexagynia, is little better than nominal; the fifth order, 
Polygynia, contains the water-plantain (. flisma, from alis, wa- 
ter, Celt.), of which several species are natives of this country; 
one, A. Plantago (fig. 13.), is very common, and might borrow 
from the heart’ ease the familiar appellation of Herb Ty nity. 
The calyx has three leaves, the corolla three petals ; the cap- 
sules, of which there are six, are ranged in a 5 
triangular form; the flower-stalk is three feet & Yeoer, 
high, and the upper part clothed with flowers, ra yer 
set in whorls infinitely compound: ed, six in 
each whorl, three twice the size and length of ese — 
the alternate three. Where this plant iS ya 
luxuriant, the subdivisions of the whorls are 
innumerable. Wherever a pond is to be 
found, the water-plantain is to be found by 
the sides of it. It blossoms in the month of 
July, and is seen to most advantage at about two or three 
o’clock in the afternoon ; after fee. time its thin and some- 
what crumpled petals begin to droop. 
(To be continued.) 
Art. XIV. Introduction to Geology. 
(Continued from Vol. 1. p.453.) 
GEOLOGICAL SYSTEMS OF ARRANGEMENT. 
Ir has been seen in our introductory article on the pro- 
ress of geology, that the researches of geologists, commencing 
with Werner, Saussure, Mitchell, and Smith, led to the dis- 
covery of certain laws relative to the origin and succession of 
rocks. Various terms have been employed in their classifica- 
tion. It was long considered sufficient to divide them into 
two great Glasses: the Primary, consisting of rocks whose 
Sennen is chemical only, and possess no traces of or- 
ganic beings; and the Secondary, consisting of rocks whose 
st ucture is chiefly mechanical, and which contain numerous 
substances of obvious vegetable and animal origin. = This ar- 
rangement was Fecormmended by its simplicity, and the facility 
it affords of referring the different rocks to one or more of 
these great divistonge 
In order to distinguish the more recent portions of the class 
before named Saconds ary, a further division was suggested, and 
the term Tertiary has been adopted by most oeologists, as 
designating the strata which were deposited successively over 
