124 PROCEEDINGS OF THE 



colouring nucleus of the red clays. But while this part of 

 the theory did not admit of general application, the conclusions 

 arrived at regarding the conditions under which the old red 

 sandstone and pernio-triasic strata were laid down remained 

 untouched, since these latter were sandy deposits, shale being 

 very subordinate. 



The occurrence of a non-calcareous accumulation in the deepest 

 waters was next discussed, as bearing on Professor Hull's views 

 regarding calcareous rocks. After stating the still debated issue 

 as to the decalcification of the Globigerina ooze and the conversion 

 of the non-calcareous part into red ooze, Dr Young suggested 

 that perhaps we have not yet recognised the deepest water 

 accumulations, which, if the events .of the remote past are 

 identical with those of the present, must have corresponded to 

 the mountain limestone or the chalk. Again, the area over 

 which the calcareous material might be spread was shown by the 

 distribution of the coral mud at the present to be far greater than 

 that occupied by the animals whose skeletons went to make up 

 the deposit. Moreover, oscillations of the ocean floor might bring 

 into seeming succession to each other accumulations which were 

 in reality contemporaneous, and Dr Young dwelt on this as 

 helping to bear out the suggestions contained in his British 

 Association address, to the extent, that the thickness of the 

 stratified deposits, and, as a consequence, the time required for 

 their deposition, might be over-rated. The uniformity of aspect 

 presented by the deep sea fauna has an important bearing on the 

 views of Salter and others, who regard the wide distribution of 

 mountain limestone fossils as evidence of the greater uniformity 

 and consequently smaller number of types of animals in the 

 earlier period. If we have to do with the inhabitants of deep 

 waters in these limestone fossils, there might have been, and 

 probably was, at these early times, as great a diversity as now. 



After glancing at the controversy regarding ocean circulation, 

 and pointing out wherein the data were as yet incomplete, on 

 Avhich a satisfactory judgment could be based, Dr Young referred 

 to the question of the possible increased salinity of the existing 

 seas, and asked if Mr Buchanan's results, when fully wrought out, 

 might not support, by the constancy of high specific gravity below 

 certain depths, the notion that the ocean might be, as has been 

 suspected on theoretical ground, Salter than it once was; in f\ict, that 



