4 Review of the first Volume of M. J. A. De Luc's 



Whether the present rivers and streams of water > have ex« 

 cavated the valleys through which they flow P a question, 

 which some months ago exercised the pens of two of your 

 correspondents, I recollect. M. De Luc seems to consi- 

 der it as fully proved, by the numerous facts which he 

 adduces in the volume before me, that rivers and brooks 

 have no tendency to deepen their channels, but, on the 

 contrary, are in every instance, with greater or less rapidity, 

 filling up the bottoms of the valleys with the matters 

 which they sweep away from the fett of the flailing cliffs 

 and steep banks that they undermine, in the more rapid 

 parts of their courses : and that the whole of trje matters 

 so removed by the currents of rivers, are dropped before 

 they reach the depths of the ocean, and arc even met by 

 and mingled with large quantities of pure sand, thrown up 

 by the tides, from such deep parts of the ocean. The 

 growth and operation of peat, in filling up some vales, is 

 exemplified by instances at pages 131, 137, 146, 24 7, 334, 

 344, 8cc; and in lessening, if not at length entirely filling 

 up and obliterating, lakes, and natural pools of water in 

 other instances, af pages 138, 141, 144, 145, 146, 14 7, 17 I, 

 1<85, 187, 190, 191, 233, 275, 281, 344, 347, &c. 



The 12th, 1 6th, and 17th heads, relate to the question 

 Whether the holders or blocks of granite and other stones, 

 have emigrated on the surface of the earth P The instances 

 are very numerous which M. De Luc describes, through 

 his whole route from Berlin to Husum, of blocks of granite 

 and other primordial stones some of stupendous size, and of 

 various species, found on the tops of graveily eminences, 

 in the face and at the feet of gravelly cliffs by the sea side, 

 and on some plains, at pages 123, 127, 129,135, 137, 

 156, 160, 172, 173, 178, 180, 181, 194, 195, 205, 213, 

 220,223,224,2-26, 228, 234, 237, 238, 248, 251, 249, 

 255, 256, 257, 265, 272, 273, 274, 277, 278, 2/9, 285, 

 291,293, 301,302, 30*, 313, 323, '329, 333, 334, 344, 

 367, 373, 381, 384, 366, 387, 388, 8cc. These instances 

 are considered by our author as concurring in proving, the 

 impossibility of such blocks being transported along the 

 present or any former surface of the earth, to the places 

 where they are now found, and as establishing or gene- 

 ralizing the supposition made by Mr. Wraxall and M. Dr 

 Saussure in particular instances elsewhere, thai such blocks 

 u seemed as if they had fallen from I he sky." 



I confess, however, sir, that I was somewhat disap- 

 pointed in finding no attempt in all these details, at pointy 

 jug out the exac? places of the crater- ftke orifices, whence 



these 



