MINERALOGY. 



411 



Cofiiosy. have distinct characters of difference. In the first 

 S- *"Y"*' and second i>eriods, the productions are aUmost entire. 

 ly chemical, but the crystallization becomes more im- 

 ptrrtect, tlic newer the formation. Lastly, in the third 

 period, the members of the series become mixed with 

 small portions of mechanical matter, as is shewn by 

 the earthy aspect of many flcetz-limestone*. We know 

 the condition* necessary for the formation of a crystal- 

 line structure, and that rest and motion are the agents 

 which assist or prevent its regular formation. Hence 

 we may fairly infer, that the solution, or ocean when 

 it stood high over the earth, was calm and undisturbed. 

 During succeeding periods, the solution appears to have 

 become more and more agitated ; yet at first it only pre- 

 vented the perfection of the crystallization. As the water 

 diminished in height, its motions increased ; its destroy- 

 ing powers reached to the surface of the earth, and the 

 crystalline shoots were destroyed, and thus the first me- 

 chanical productions were formed. The water still con- 

 tinuing to diminish, the dry land began to appear ; of 

 course the mechanical action of the water would be 

 much increased, a* also the formation of mechanical 

 productions. How admirably dues this agree with the 

 appearances presented by this series of formation* ! 

 The conne 



nnection an 



import of all these 



will be more apparent, if we take a view oft 

 teristic position of the strata in the different members 

 of this series of formations, and of their relations to the 

 exterior of the earth. This will be considered particu- 

 larly afterwards. At present we shall only mention the 

 highly elevated level of the limestone in gneiss), ees> 

 trasted with the low situation of chalk and calc-tuff". 



2. Slate Formation- Suite. 



This is a very extensive series of formations *. The 

 limestone series is composed only of limestone, and a 

 single earth as its principal constituent part. In the 

 series of clay-slate formations, on the contrary, different 

 earths have united together, to form the rocks we shall 

 now mention. Silica, alumina, and magnesia, but par- 

 ticularly the two latter, are the most characteristic 

 earths belonging to this suite of formations. We shall 

 begin the description with that member of the series 

 . may be considered as a central point from which 

 the others diverge, and which gives the name to the 

 whole series. This is clay-slate. It is evident, that 

 the oldest clay, slate must border on the newent Mica, 

 slate ; and the newest, on transition-slate. The oldest 

 clay-slate has more lustre than the newer, and is even 

 slightly micaceous, so that it resembles the fine slaty 

 mica slate on which h rests. The newer clay-slate has 

 a darker grey colour, less lustre, and contains finely 

 disseminated scales of mica, which brings it nearer to 

 the transition-slate. Mica-slate is an sggregate rock, 

 composed of ouarts and mica : but in the older, it be- 

 comes gradually intermixed with felspar, which, in the 

 oldest varieties, increases and shews itself more and 

 more as an essential constituent part, until the mica- 

 slate passes into gneiss. The texture of the newest 

 gnei* which lies nearest to mica slate is still thin slaty ; 

 but it becomes gradually coarser, more crystalline, 

 thick slaty, and vry nearly granular, when it passes 

 into granite. In granite, the Uxture is completely 

 granular, and this rock stands as the first and oldest 

 member of the terie*. 



The sasne due will conduct us back to the trsnsi- 



tion-slate, which occurs in mountains of grey-wacke. 

 Here distinct mechanical matter is mixed with the 

 chemical. Grey-wacke is a complete sandstone : we 

 have a gradation of its grains from those the size of a 

 pebble, until, from their smallness, they are no longer 

 distinguishable ; and this constitutes a transition to 

 grey-wacke slate. 



Sandstone, and sandstone-slate, are the next members 

 of this series. The sandstone-slate resembles mica- 

 slate so much, that it has been sometimes confounded 

 with it. To the sandstone succeeds the coal formation, 

 which contains friable sandstone and slate-clay. Lastly, 

 the series is terminated by bituminous wood and earth- 

 coal, accompanied with sand and clay ; which latter 

 correspond to the sandstone and slate-clay of the im- 

 mediately preceding formations. 



A material division of this beautiful series takes 

 place with grey-wacke. From it, upwards, all the 

 members are completely chemical. On the contrary, 

 in the lower, the chemical is combined with mechani- 

 cal, and only the lowest links of the series are com- 

 pletely mechanical productions. 



5. Trap Formation-Suite. 



In this series, all the formations have a great resem- 

 blance to each other ; yet all of them bear very distinct 

 marks of the period of their formation. The oldest or 

 primitive greenstone is highly crystalline ; the newer 

 or transition is lets crystalline ; and in the newest or 

 trap, it approaches to earthy, as appears in ba- 

 salt, and more particularly wacke, as the lowest links 

 or farthest removed from the highly-crystalline primi- 

 tive greenstone. 



4. Prophyry Formation- Suite. 



The first member of this series, or which is denomi- 

 nated the Old Porj>hyry Formation, occurs in great un. 

 broken beds, in gneiss, and its basis is homstone. 

 The second member, or what is denominated the A'r r - 

 er Porpkyry Formation, occurs in unconformable, over. 

 lying, and broken stratification. Its basis is clay- 

 stone, pitch-stone, &c. The third and last member of 

 this suite is probably the clay-stone, and porphyritic- 

 stone which occurs in the coal- formation. 



5. Gyptum Formation' Suite. 



The oldest member of this formation occurs in mica- 

 slate and clay-slate. The second member is that which 

 accompanies salt, and with which salt-springs are con- 

 nected. It lies over the old flirtz-lirneMone, 'and is 

 covered by the second flcctz-sandstone. The third and 

 last member, is what is denominated the second gyp- 

 sum formation of the Ilirtz period. It lies over the se- 

 cond sandstone formation, and under the second lime- 

 stone of the fla-U period. 



6. Salt Form ft ion- Suite. 



This series contains only two members. The first 

 and oldest occurs along with the oldest flortz gypsum, 

 and the newer is that which is still forming at the bot- 

 tom ot the lakes. 



7. Coal Formation-Suite. 



This i* a very interesting series. Inflammable mat- 

 ter occurs in considerable quantity only in the newer 

 formations. The small portion that occurs in primi- 

 tive mountains, is carbon, uncombined with bitumen 



Trap for- 



mation- 

 fuilc. 



Porphyry 

 formation- 



iult '* 



Gjpjnm 

 formation 



sn forma. 

 tion-suiic. 



Coal forms. 

 tion mitt. 



Ifwr 



ate. 



righiljr, * 



tfct propriety of the name gino to thai tenet, 



it in th wbok or go the great acale. 



it extttm* members, it would appm y unappropri- 



