4.06 Mr. H. G. Seeley on the Laws ivhich have determined 



forms, discharging rock-matter into tlie sea; while the settling- 

 down of these materials upon the sea-bottom is the work deter- 

 mined by gravity. The motion of matter around the land is 

 for the most part due to the tide-generating power of the sun 

 and moon ; but the arrangement of this matter on the sea- 

 bottom is due to gravity. 



3. The motion of living things on land is due primarily to 

 the sun's heat distributing the individual species in zones of 

 uniform temperature, moditied by movements in the earth's 

 crust producing distribution irrespective of temperature. The 

 distribution of living things in water is due primarily to move- 

 ments in the earth's crust, moditied subsequently by the form 

 of coasts, the abundance of life, and by temperature. 



4. On the hypothesis of the earth having cooled from a fiery 

 state, the surface-rocks would be uncrystalline granitoid sub- 

 stances, the denudation of which would furnish clays. But, as 

 a matter of fact, everywhere beneath stratified formations some 

 rock of a granitic character is found. Therefore, assuming all 

 stratified rocks to be derived from the denudation of plutonic 

 rocks, it is necessary to consider what stratified deposits such 

 denudation can result in. 



5. If the plutonic rock is crystalline, a granite may be taken 

 as the type. It consists of quartz, felspar, and mica — speaking 

 roughly, in the proportions of 25 per cent, of quai'tz, 55 per 

 cent, of felspar, and 20 per cent, of mica. The quartz is heavy, 

 and washes out in grains, which, left behind, form a deposit of 

 sand. Hence, if granite w^ere the only source of water-formed 

 rocks, and only denuded by the sea, one-quarter of all known 

 stratified rocks would be sands and sandstones. And therefore 

 the quartz-grains (the sandstone to be, or that is) will form a 

 belt near to and around the shore, and will always be indubit- 

 able evidence of near vicinity to land. And supposing the mica 

 not to be decomposed, from its fine flaky character it will, 

 according to circumstances of slope of sea-bottom, currents, &c., 

 be cari'ied either to the limit of the sand, and go to form a 

 micaceous sandstone, or go beyond the limit of the sand, and 

 form a micaceous clay (slate). 



The felspar readily decomposes into a clay, setting free in 

 addition a quantity of silica and potash or soda ; and, from the 

 extreme fineness of its particles, this clay is carried out to sea 

 further than the sand, and surrounds the land as an outer belt, 

 at least twice as broad as the sand-belt. 



But if the denudation takes place on the land- surface by the 

 agency of rain and running water, the major part of the sand 

 will be left behmd, and the detritus poured into the sea by the 



