INTRODUCTION. 



ness and their relative positions. By its general appear- 

 ance, and by the aid of simple tests in the field, or if 

 necessary, more complicated ones applied to detached 

 specimens at home, we ascertain the kind of rock of 

 which any bed or series of beds consists. By this means, 

 and by the determination of the Fossils collected from 

 such bed or series of beds, we are enabled to assign to it 

 its position as belonging to a certain formation, or 

 possibly even to a definite horizon in such formation. 



Thus we see that, to obtain an accurate knowledge 

 of the structure of a district, to represent and describe 

 its geological features, and to be able to generalise there- 

 from, four distinct and different, although intimately 

 connected, operations have to be performed. The strata 

 which crop out at its surface must be traced, and their 

 boundary laid down upon the map. The dip (if any) 

 and the underground continuation of the beds worked 

 out the character, peculiarities, and geological age of 

 the rocks ascertained, and their fossil contents discovered, 

 determined, and classified. Each will be treated of 

 separately as far as possible, under one of the following 

 heads 



1. Geological Mapping. 



2. Sections. 



3. Lithology (Determination of Rocks). 



4. Palaeontology ( Fossils). 



The directions given in each Part will be simple and 

 elementary, assuming the student to possess a fair book- 

 knowledge of the science, of its theory, of the sequence 

 of the various systems, formations and groups, and of 

 the general succession and range of fossil plants and 

 animals. By giving examples of the method in. its 



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