Classification of Rocks. 15 



corals, shells, numerous fish, and some remains of Sauriana. The furmation 

 IS widely spread out over liussla, and occurs also in Englaiul, hut not in 

 ('auada. 



K. Caeboniferouf!. 

 28. Upper Carboniferous ; 29. Lower Carboniferous. — The first 

 of these contains tlic beds of coal, and is of great thickness in some places. 

 Sir Charles Lyell says, that " in South Wales the coal measures liavc been 

 ascertained by actual measurement to attain the extraordinary thickness of 

 12,000 feet ; the beds throughout, with the exceptio]i of the coal itself, ap-- 

 j^aring to have been formed in water of moderate depth during a slow, but 

 perhaps, intermittent depression of the ground in a region to which the rivers,, 

 were bringing a never faihng supply of muddy sediment and sand. The 

 game area Avas sometimes covered with vast forests, such as we see in the 

 deltas of gi'cat rivers in warm climates which are liable to be submerged 

 beneath fresh or salt waters, should the ground sink vertically a few feet." 

 The process appears to have been carried on as follows :— Large tracts of 

 low level and marshy laud near the mouths of great rivers remained clothed 

 with vegetation until the fallen leaves, branches, trunk's of trees, ferns and 

 reeds, formed beds of vegetable matter several feet in thickness ;. the land then 

 sank beneath the level of the sea and the surface became covered over v/ith 

 more or less numerous strata of sand and mud. An elevation then took place 

 — a new forest with a new^ bed of vegetable soil was formed; the country again 

 subsided, and the materials for other strata of rock were spread over its sur- 

 face, while at the bottom. Thus one bed of coal after another, was formed 

 with layers of limestone, sandstone, or shale between. In the coal mines, 

 the stumps of the trees are often found with roots imbedded in the spot where 

 they grew. In 1852, Prof Dawson, (now the Principal of McGill College,. 

 Montreal,) and Sir Charles Lyell, found in one locality, called the Joggins, 

 in jSTova Scotia, GS of those buried forests one above the other in a depth of" 

 1,400 feet of rock. Mr. Logan had previously ascertained that the thick- 

 i>es3 of the formation at the same place is 14,750 feet, nearly three miles, so 

 tiiat there may be many others besides those observed. It appears to be 

 well established that coal is entirely of vegetable origin, and that each bed: 

 now occupies the spot where the plants from which it was derived' grew. — 

 During the age of the formation of the coal the land, was stocked with a 

 most prolific vegetation. In England, Europe, North America, and even- 

 in the Arctic regions wdicre only a few dwarf shrubs and' mosses now grow ; 

 there were in the carboniferous age of the world dense forcstvS similar to those 

 of the tropical regions of the present day. There were many large fish in- 

 the seas, and it appears a few air-breathing reptiles on land. The lower car- 

 boniferous rocks contain no coal- The true coal measures, or the upper 

 carboniferous formation does not occur in Canada, but a portion of the 

 lower carboniferous reaches Guspe at the Bay of Chaleur. Both are exten- 

 eive'y developed in Nova Scotia and' New BVuuswick.. 



