32 Professor Spencer — Continental Elevation. 



from Lower Gault to Chalk (Echinoconus castaneaf), is hardly 

 sufficient evideuce to warrant the conclusion that a part of the 

 rock-mass was of Upper Greensand age. There is nothing except 

 the Am. SelUgiiinus that is specially characteristic of the Gault, 

 and the question is this : What is the evidential value of the 

 occurrence of J^chinocyphiis difficilis, and possibly also of JEchinocomis 

 castanea (?) ? I think it may be answered in this way : it is more 

 reasonable to suppose that these two species, or forms very closely 

 allied to them, date really from Lower Cretaceous times, than it is to 

 suppose the deposition of exactly the same kind of rock material 

 should have continued at any one place from the time of the 

 Lower Greensand to that of the Upper Greensand. In other 

 words, I believe that the rock-mass from which the Moreseat fossils 

 have been derived was entirely a Lower Cretaceous rock, but high 

 in that series, and corresponding approximately to the Aptien stage 

 of France, and to the Lower Greensand or Vectian of the Isle of 

 Wight. 



VI. — On the Continental Elevation of the Glacial Period. 



By Prof. J. W. Spencer, M.A., Ph.D., B.Sc, F.G.S. 



Contents : 



Introduction. — Character of the Submarine Antillean Valleys. — Gradients of Sub- 

 marine Valleys.— Date of the Continental Elevation. — Migration of Mammals. — 

 Submarine Channels off the Eastern Coast of America. — Submerged Plateau of 

 the North Atlantic. — Continental Elevation a Cause for Glacial Climate. 



Litroduction. 



BEFORE the last meeting of the British Association, held in 

 Liverpool, Professor Edward Hull presented a paper upon 

 "Another Possible Cause of the Glacial Epoch." In that paper, 

 Professor Hull applied the writer's work on the " Eeconstruction 

 of the Antillean Continent," ^ which brought together evidence of 

 great continental elevation. This elevation and its effects upon the 

 ocean-currents, in diverting them from the West Indian regions, 

 with the consequent reduction of their temperature as they reach 

 the northern latitudes in conjunction with the elevation of the land, 

 were thought by Professor Hull to he sufficient causes for the 

 production of the glacial climate over temperate regions in late 

 geological times. The writer has hitherto never applied his 

 observations on high continental elevation to climatic changes ; 

 but in this paper he proposes to extend briefly his researches 

 from the Antillean region to the higher latitudes of America 

 and the North Atlantic regions. Something has also been learned 

 of the date of the great elevation ; consequently inferences may be 

 drawn as to climatic changes. 



Character of the Submarine Antillean Valleys. 

 The feature of the paper on the " Eeconstruction of the Antillean 

 Continents," and subsequent observations of the region, show that 



' J. W. Spenoer, "Eeconstruction of the Antillean Continent" : Bull. Geol, See. 

 Amer., vol. vi, pp. 103-140, 1894. 



