304 ANNUAL OE SCIENTIFIC DISCOVERY. 



From these tables it appears that the produce of gold in .the world 

 rose from 114,674 pounds in 1846, to 365,950 pounds in 1850. In 

 those five years the increase was at the rate of 219 per cent,, while 

 silver only increased from 1,979,084 pounds in 1846, to 2,663,386 

 pounds in 1850, or 34| (34.5) per cent. The former metal was in 

 1850, therefore, apparently increasing at the rate of 44 (43.8) per cent, 

 per annum, and the latter at 7 (6.9) per cent. 



The following is the estimated produce of the precious metals, in 

 tons, in 1801, 1846, 1850, 1851, and the probable amount of 1852 : 

 1801, gold, 19 tons; silver, 856 tons, or 1 Ib. of gold to 45 Ibs. of 

 silver. 1846, gold, 42 tons ; silver, 727 tons, or 1 Ib. of gold to 17 Ibs. 

 of silver. 1850, gold, 134 tons; silver, 978 tons, or 1 Ib. of gold to 

 7 Ibs. of silver. 1851, gold, 180 tons ; silver, 1,002 tons, or 1 Ib. of 

 gold to 5 Ibs. of silver. 1852, gold, 242 tons ; silver, 1,027 tons, or 1 

 Ib. of gold to 4 Ibs. of silver. 



ON THE FOOT TRACKS IN THE POTSDAM SANDSTONE OF LOWER 



CANADA. 



MR. LOGAN, the Canadian Geologist, in his report on the progress 

 of the Survey for 1851 - 2, furnishes the following facts relative to the 

 foot tracks of the Potsdam Sandstone of Lower Canada,* The results of 

 the survey have shown, that a geological trough exists between the 

 Ottawa and the St. Lawrence on the north and south, and between Mt. 

 Calvaire and the Johnson District on the east and west ; that the 

 Potsdam sandstone, resting on the gneiss, encircles this trough, and 

 that zones of higher and more fossiliferous formations follow this in 

 succession, the Utica slates occupying the centre ; that the Potsdam 

 sandstone is characterized by Scolithus linear is around the perimeter, 

 associated, in some parts, with Linr/ula antiijua, and with the tracks in 

 every locality in which the latter occur. These localities are six in 

 number. At one locality, on the Riviere du Nord, where the tracks 

 are abundant, in the space of a mile and three-quarters, the Gneiss, 

 the Potsdam sandstone, the Caleiferous sand-rock, (the last containing 

 characteristic fossils,) are found supporting one another. The sur- 

 faces on which the tracks of these animals are impressed, are some- 

 times smooth and sometimes beautifully ripple-marked. On the 

 ripple-marked surfaces the tracks have often beat down the ripple, 

 and the sand of the ridge has been dragged into the furrow, in such 

 a way as to show the direction in which the animal was progressing. 



In the most abundant locality of these tracks, there are four exposed 

 areas in the space of four chains. The first shows ten tracks, running 

 in different directions and sometimes intersecting one another ; they 

 vary in breadth from four inches and a-quarter to five inches and 

 a-half, and, added to one another, measure 108 feet in length ; the 

 second displays eleven tracks of five to six inches wide, and measur- 

 ing about 108 feet; the third shows five tracks of from four to six 



O ' 



* See Annual of Scientific Discovery for 1851, pp. 314-15. 



