Physical Geography. 157 



Sandstone, Carboniferous, Permian, and New Red form- 

 ations, it will be seen that, by the writer, they are all 

 considered to afford evidence of continental as opposed 

 to purely marine conditions ; for the Old Bed Sand- 

 stone was deposited in fresh water, the Coal-measures, 

 whether below, interstratified with, or above the Car- 

 boniferous Limestone, on the edges of, and to a great 

 extent on, a continent with large rivers, marshes, and 

 beds of peat, and the Permian and New Red series 

 both in salt lakes ; in other words, a great continental 

 epoch in Northern Europe (and in other regions), lasted 

 from the close of the Upper Silurian epoch down to 

 the end of the deposition of the New Red Marl, one 

 main feature of ivhich was the abundance of reptilian 

 life, partly Amphibian. Those parts of it in which 

 the Permian and New Red strata were deposited can 

 be best compared physically to the great area of inland 

 drainage of Central Asia, so dry and arid where not 

 artificially irrigated by rivers, and in which, from the 

 Caspian Sea for 3,000 miles to the east, and far south 

 towards the Himalayah, in a comparatively rainless 

 district, all the lakes are salt, excepting those which 

 have an outlet into some lower lake. 



I specially draw attention to these remarkable 

 inferences, for surely they give something like a broad 

 view of an old phase of a long-enduring physical 

 geography, so long, indeed, in my opinion, 4 that the 

 great continental era, which began with the Old Red 

 Sandstone and closed with the New Red Marl, is com- 

 parable, in point of geological time, to that occupied 

 in the deposition of the whole of the Mesozoic or Se- 

 condary series (later than the New Red Marl) and to 

 the whole of the Cainozoic or Tertiary formations, and, 

 indeed, to all the time that has elapsed since the begin- 



