WORKS OF REFERENCE. 11 
The following abbreviations are also employed :— 
§ 1. Relative to the Rocks or Strata. 
Drift. Alluvial deposits, or Drift. 
Tert. Tertiary. Lond. C. London clay. 
Cret. Cretaceous formation. U. Ch. Upper chalk. 
L. Ch. Lower chalk. 
Trias. New Red Sandstone, or Triassic deposits. 
Carb. Carboniferous or Coal formation. 
Mt. £. Mountain or Carboniferous limestone. 
Devon. Devonian or Old Red Sandstone formation. 
Sul. Syst. Silurian System, or formation. 
§ 2. Relative to Organic Remains. 
nat. Natural size. 
x Magnified in diameter: e.g. x 8, magnified eight 
diameters, &ec. 
x xX Highly magnified; the degree not accurately de- 
termined. 
wmv. Invisible to the naked eye. 
— Less than natural: e.g. — 2, reduced to two-thirds 
the diameter of the original. 
Lign. Lignograph or woodcut. 
Hxplanation of Terms.—Upon the occurrence of a scien- 
tific word apparently requiring explanation, the meaning, 
where practicable, is for the most part given in a parenthesis ; 
for example, Caulopteris (fern-stem) ; Phascotherium (pouch- 
animal); carboniferous (coal-bearing); except in the case 
of arbitrary names, and of those whose derivation cannot be 
concisely expressed.* With the view of rendering these 
volumes more generally useful, English terminology is in 
* Upwards of 300 scientific terms are explained in the Glossary, 
“ Wonders,” vol. ii. p. 915—921. 
