Natural History. 35 



found further to the north in England, in 1866, than at 

 Coptheath near Birmingham, and at Abbots Bromley in 

 Staffordshire ; when, in that year, as the gradients of the line 

 between Gainsborough and Lincoln were lowered, I had the 

 satisfaction of meeting with them. Since that time they have 

 been discovered, in a nearly continuous line, across England 

 from north to south, wherever the jun&ion of the Trias and 

 Lias is exposed. 



Some geologists place these beds at the top of the Trias, 

 others at the base of the Lias, or Jurassic, system. This, 

 however, is a matter of small importance. They are the 

 passage beds from one great system to another, from the 

 deposits of the upper Keuper lake to those of the great Liassic 

 sea ; beds which go far to unlock the hidden story of the land 

 we are considering. 



About the origin of the bone beds referred to, much 

 speculation has taken place. 



Mr. Jukes Browne, in his work on "the building of the 

 British Isles," to which I am indebted for several of the facl:s 

 stated in my paper, speaks of the irruption of the sea water 

 being prejudicial to the inhabitants of the Triassic lake, "so 

 that most of them died, and their bones, scales and teeth were 

 drifted into layers on the sea floor;" but this, I think, could 

 hardly have been the case, as, apparently, the concentrated 

 saltness of the lake had, to a great extent, prevented the 

 possibility of life no trace of it, except in a few localities, 

 being met with throughout the system ; and this view Mr. 

 Jukes Brown himself bears out, when, in another part of his 

 work, speaking of the Triassic lake, he says, " the sheet of 

 water being apparently as salt, as clear, and heavy, and as 

 nearly lifeless as the modern waters of the Dead Sea, or of the 

 great salt lake of Utah." May not these beds be rather due 

 to the fishes, which the Liassic sea brought in, being killed by 

 the salinity of the waters of the inland lake ? or, perhaps, after 

 life had developed through the change of water, the land 

 temporarily rose again, or became stationary for a time, and, the 

 salinity returning, the fishes, no longer able to sustain life, 

 perished, and their remains sank, in a layer, on the sea floor. 



There is another facl: of interest connected with the 

 Rhoetics which must not be omitted before we leave them, 

 and that is, that the earliest known British mammal the 

 Microlestes a small insect-eating animal is found within its 

 strata. The Rhoetic beds contain also remains of the huge 



