70 RAMSAY AND EVANS. — OBSERVATIONS IN GEOLOGY. 



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c. It may happen that the strata do not 

 dip regularly in any given direction but are 

 bent and contorted, and this should be noted. 

 In all cases observations of their fossil and 

 other contents should be registered similar to 

 those mentioned with regard to the supposed 

 horizontal strata, that is to say, in serial 

 order. 



d. It is of great importance to notice if all 

 the strata in a given section lie conformably 

 on each other as they do in the preceding 

 diagrams, or if unconformable stratification 

 is obvious, or may^be inferred ; cases of which 

 are shown in the diagrams, Figs. 4, «, ^, c, d. 



If so then it is probable that the strata 

 numbered 1 will be found to belong to a much 

 earlier period of geological time than those 

 numbered 2, and if the strata are fossiliferous 

 that some of the genera and most or all of the 

 species will be distinct in the formations that 

 lie unconformably to each other. 



e. Interstratified with common sedimentary 

 strata there are often beds of coal, lignite, 

 gypsum, rock salt or other minerals to be 

 found, and they sometimes contain pseudo- 

 morphous crystals of rock salt in marly, shaley, 

 or sandy bases, for these often remain where 

 no solid beds of salt are found. These cir- 

 cumstances are of importance as indicating 

 terrestrial surfaces where the plants, the fos- 

 silized remains of which form coal and lignite, 

 grew, and in the case of gypsum and salt, to 

 the probable existence of inland lagoons and 

 salt lakes in which gypsum and salt were 

 deposited. 



Note and collect any other minerals in the 

 rocks that seem to be of scientific importance. 



It is also very important to note the colour 

 of the rocks, grey, green, brown, blue, or red, 

 &c., as the case may be, and also the effect 

 of weathering on the surface of the rocks. 



Igneous JRocks. 



f. Arc any of the ordinary stratified formations associated with 

 igneous rocks such as bosses of granites, syenites, quartz-por- 



