Whilst the primitive mountains were still covered with water, it is supposed that a considerable rising of the waters took place, from which were deposited rocks of porphyry, sienite and pitch-stone. These contain very little mechanical de position, no petrifactions, and little or no carbonaceous matter. These rocks are considered as the second porphyry and sienite formations.
The rocks which are considered as transition rocks are, 1. Transition lime stone, differing from the primitive in its variety of colours, and by its containing the remains of marine animals ; and from the fl oetz in its minute granular structure giving a splintery or flat conchoidal frac ture. 2. Transition trap ; under which species we have transition green stone, distinguished by being less crystalline than the primitive, and more so than the fioetz ; and transition amygdaloid. 3. Grey wacke, which. is more abundant than the two preceding, and also marks a particular period in the formation of rocks, it possessing the appearance of me chanical deposition. There are two kinds, grey wacke and grey wacke slate : the former is a sand-stone, differing from those of later formation, in being compos ed of portions of sand of larger size in grey coloured clay-slate ; the latter ob tains its slaty structure, in a great mea sure, from the smallness of the sandy par ticles. This rock is extremely abundant in metals, and is very generally distribut ed. 4. Transition flinty-slate. 5. Tran gypsum. The two latter do not appear to be decidedly • distinguished from those ofthe other periods.
The floEtz rocks, formed by risings of the waters after the creation of animals and vegetables, seldom reach to a very great height : those of what is termed the newest floitz trap formation form, how ever, an exception ; since they cover the summits of very high mountains, and show their formation to have been at a different period, and when the waters were higher than when the other flatz rocks were formed. Of these rocks lime stone is the most prevalent ; and in the rocks of this formation bituminous fossils, and the petrifactions of vegetables and animals, are very numerous, and in great variety.
The rocks of this class are the follow ing: 1. The first sand-stone formation, which is called the old red sand-stone ; the grains are usually quartz and flinty slate, cemented by iron-shot clay. 2. Variegated sand-stone, or second sand stone formation ; which is marked with, and is also disposed in, layers of different colours. 3. Third sand-stone formation ; which is always white, and appears to be of much later formation than those just mentioned. 4. Partial sand-stone forma tion. 5. PloEtz lime-stone, is a simple rock, and is more distinctly stratified than any other rock. Two distinct formations
are described ; the first floEtz lime-stone, and the second floEtz, or shell lime-stone. 6 FloEtz gypsum is also a simple rock, and is more or less distinctly stratified. Of these rocks also there appears to be, beside others, two principal formations. 7. Rock-salt formation. It is mostly found in short, but thick beds, in clay in a state between common and indurated clay. 8. Chalk is reckoned one of the newest of the floEtz fbrmations. It generally con tains flint, and the petrifactions of marine animals. 9. Flatz trap is supposed by Mr. Jameson to result from a formation different from that which Werner has named the newest flatz trap. 10. Coal formation. Werner describes three for mations of coal ; the oldest, or indepen dent coal formation; that which occurs in the newest flatz trap formation ; and that which occurs in alluvial land. 11. New est floetz trap formation, which includes several rocks, particularly basalt, wack6, grey-stone, porphyry-slate, and trap-tuff, which are its peculiar and characteristic rocks. Those which occur in it, as well as in the other floEtz formations, are green-stone, amygdaloid, pitch-stone, ob sidian, pumice, compact felspar, clay stone ; gravel, sand, and clay ; sand-stone. clay iron-stone, lime-stone, iron-clay, and coal. The form, and other visible cha racters, of many of the mountain rocks are frequently sufficient to point out their nature to the attentive observer. Granite is characterised by its very high and precipitous cliffs and peaks ; gneiss is less lofty, and its summits are less steep and abrupt ; and the mountains of mica slate are still less lofty, and bear more of a rounded form. Clay-slate mountains are generally less lofty than those already. noticed, and their cliffs are still less steep and rough. Primitive lime-stone some times presents lofty peaks, like those of granite ; but the mountains containing it in general assume the characters of gneiss, mica-slate, or clay-slate, with which it is in general found. .Rocks of primitive trap are generally lofty, steep, and conical. " No rock," Mr. Jameson observes, " presents a greater variety of external appearance than the sand-stone. Its val lies are deep, rocky, and romantic ; its hills are conical, steep, and cliffy ; and it often presents grand colossal pillars, which, from their number, and variety of their shape, form most striking rocky scenes." Floetz lime-stone assumes very different forms from those already parti cularised, being extended in large, flat hills, intersected by steep vallies. Chalk in some situations forms hills of consider able height, which are generally round ed, with an extensive base.