56 REVIEWS. 



occasionally into pictures, when palms, bamboos, &c, should have appeared. 

 The consequence was disastrous ; so is it in the eye of the geologist, or 

 indeed of any one who uses his eyes in observing, when, in pictures, artistic 

 rocks take the place of real ones. Though the illustrations of our author 

 would, at first sight, make us think that no fancy could be so wild as to 

 produce a rock scene, of which a likeness could not be found, it is not 

 so. There is a character in nature which is not to be trifled with. We 

 earnestly recommend this work to all landscape painters, and to all gentle- 

 men geologists. As a sample of its style take the following — 



u I do not know that we can commence an elementary book on geology in a 

 better way than by asking the reader if he knows what sand is. Because any one 

 who thoroughly understands the origin and nature of common sand — whether it be 

 found in the gravel-pit, in the river-bed, or be " the ribbed sea-sand " of the shore — 

 has made no despicable commencement in the study of the science. 



" If the reader will examine a handful of sand by the aid of a lens, he will find 

 that it is composed of grains, or minute, irregularly-shaped particles of a hard, 

 shining, often semi-transparent substance. These particles are, if not round, very 

 much rounded, often having on the surface a rubbed appearance, as if they had been 

 worn and ground against each other. 



11 As to river or sea sand, it is obvious that this rubbing must actually have taken 

 place, because, as the moving water must frequently wash the sand about, and roll 

 it onwards in its course, the particles must be constantly exposed to friction against 

 each other, or against whatever substance it may be that lies at the bottom of the 

 water. It is clearly possible, therefore, that all river or sea sand may have been 

 produced, or brought into the state of sand, by the action of the running or moving 

 waters tearing away fragments of rock, breaking them up into constantly diminish- 

 ing particles, and, by perpetual friction and rolling, grinding those particles into 

 small rounded grains. 



" If this mode of formation be true for all sand found now beneath or on the 

 margin of any moving water, it is, a priori, highly probable that all sand whatever, 

 even that of the wide deserts of Sahara, the sands of Arabia, or those of the centre 

 of Australia, have been thus formed. 



" If we come to consider of it, indeed, there appears to be no other at all likely 

 method by which sand could, in any case, be formed, unless it were originally 

 created as sand, such as we now find it. 



" Let it be taken for granted, then, for the present, as the reader sees its great 

 probability now, and will be quite convinced of its truth hereafter, that all sand was 

 produced by the action of moving water on solid rock. 



" It is, however, by no means necessary to suppose that the water always detached 

 the sand directly from the rock as sand — that is, in small grains. On the contrary, 

 if we examine the action of moving water, now whether we go to the rapids and 

 cataracts of rivers, or to the breakers of the sea battering against a rocky coast, we 

 shall everywhere see large blocks of rock lying about, often but newly detached 

 from their original site, with all their angles sharp, and the fractures fresh, the yet 

 unhealed scar perhaps plainly visible in the cliff above. We should see, also, blocks 

 having every gradation of form, from this newly-broken angular fragment to 

 smaller and smoother, well-rounded boulders and pebbles, having every projecting 

 angle ground off, and all the surface worn as smooth as a billiard-ball. This has 

 been effected by the frequent moving and rolling of all these blocks, one against 

 the other, on the pebble-beach or in the bed of the torrent ; every roll removing 

 some little corner, chipping off some little projection, each separated fragment 

 being itself shortly smoothed and rolled into a pebble or shingle, and all the waste 

 of this process being carried off by the moving water in the shape of sand. 



" We come then now to look upon not only all sand as a water- worn material, 

 but upon every pebble and every detached stone, of whatever shape and size, 



