ANNIVERSARY ADDRESS OF THE PRESIDENT. xlvii 



may be open to us ; but looking at tlie distribution of the salt amid 

 such accumulations as those noticed by Mr. Ormerod, and at the in- 

 formation (scanty though it may be on some very essential points) 

 which we possess respecting the saline lakes and salt deposits of the 

 great depression of Asia, it would be very desirable to have careful 

 comparisons made as regards the probable accumulation of the saline 

 deposits of England from the evaporation of salt water in minor basins 

 amid mud and sand. There are many interesting facts of importance 

 in this inquiry known as to the isolation of minor portions of the 

 lakes in the great depressed area of Asia, the evaporation in which 

 appears more considerable than the supply of water. After a long 

 lapse of time salt not only constitutes great cakes, or lenticular masses 

 of various dimensions and forms, but remains also in the dried-up 

 ground ; the latter finally so deprived of moisture in many localities 

 as to be blo"VMi about, forming deserts. The water eventually remain- 

 ing is gathered here and there in salt lakes, more or less modified in 

 their saline contents by the various salts carried by running waters 

 into them, and they will remain as such so long as the supply of rain- 

 and river-water equals the evaporation. We should expect salt to be 

 well-diffused amid sands and mud accumulated in the sea, and not to 

 be washed out except under conditions, such as that of the so-formed 

 beds being elevated above the ocean-level, when the percolation of 

 waters derived from the atmosphere would carry off in solution the 

 chloride of sodium and soluble matter, restoring to the sea that which 

 had been entangled amid the deposits previously formed in it. In 

 point of fact, we find chloride of sodium a very common substance 

 in spring and river waters. 



From the pattering about of reptiles at the period of our new red 

 sandstone, as shown by their foot-marks left in certain localities, we 

 may infer, whatever the inequalities and varieties of depths may have 

 been after the exertion of the force which so disturbed the coal- 

 measures and other older rocks of the British area, and thrust a por- 

 tion of them as dry land into the atmosphere, that as the deposits 

 went on very shallow water skirted the lands. With shallow water 

 slight changes of the relative level of sea and land would produce 

 considerable surface modifications. Many depressions around the 

 coast of the British islands would be converted into salt lakes if the 

 bottom of the surrounding seas were elevated, and the sea- water left 

 evaporated, should there then be an insufficient supply of rain-water. 



The mode of occurrence of the footprints abo\'« noticed is such, 

 more particularly when we regard the evidence of cracks filled up in 

 the same beds, that we can scarcely doubt the mud or silt upon 

 which the animals trod to have been subaerial at the time, and that 

 it was afterwards covered by water bringing detritus with it. In 

 estuaries or gulfs where spring tides attain a great height, such as in 

 the Bristol Channel or in the Bay of Fundy, the space left between 

 spring and neap tides is often considerable, and the tracks of birds 

 and mammals are common upon the mud so exposed, particularly 

 those of the former. In summer weather this may be well seen on 

 the shores of the Bristol Channel near the embouchures of the Avon 



