762 ME. F. W. HAKMER ON THE [Nov. 1 896, 



freshwater shells, which Dr. Lorie considers to he ' Quaternaire.' 

 Similar species occur at Utrecht and Amsterdam, associated with 

 marine mollusca of Pliocene age, such as Nucula Cobboldioe and 

 Tellina joroetenuis. In the section (fig. 4) I have drawn the hase of 

 the Pleistocene where Dr. Lorie puts it, but I have also indicated by 

 dotted lines the limits within which land and freshwater species 

 have been found. Dr. Lorie classes the strata found at Gorkum 

 below 382 feet as Scaldisien. They contain, however, Leda 

 Janceolata, and other shells, not known either from Walton or the 

 Scaldisien of Belgium, and which have not been found in the Dutch 

 borings in what I consider to be undoubtedly Scaldisien strata. It 

 seems to me that all the Gorkum beds are newer than the 

 Scaldisien. 



The Utrecht boring was carried down to the great depth of 

 1198 feet. At tbis place Dr. Lorie concludes, chiefly on lithological 

 grounds, that Diestien strata were reached at 775 feet. He points 

 out that at that depth an abrupt change takes place in the ap- 

 pearance and character of the sediment, yellow sands, witbout 

 glauconite, being replaced by grey sands containing that mineral. 1 

 As, however, the Scaldisien beds of Antwerp and Goes contain 

 glauconite, 2 this fact does not seem of sufficient importance to 

 outweigh the palaeontological evidence, which induces me to think 

 that the division between the Scaldisien and the Diestien should be 

 placed somewhat lower, namely, at 898 feet, and that the line of 

 775 feet should be regarded as the division between the Scaldisien 

 and the more recent beds. Similarity of composition is not always 

 a conclusive test of age. The material now covering the bottom of 

 the British seas is not by any means uniform over considerable areas, 

 while beds which closely resemble each other may be of different 

 age. The principal part of the material of which the Dutch beds 

 are composed was, no doubt, brought down by the Rhine and the 

 rivers associated with it. The nature of these different sediments 

 would remain more or less the same during long periods of time, 

 but they might be deposited now in one place, and now in another. 3 



At Utrecht the freshwater species, Succinea elegans, was met 

 with between 521 and 542 feet, 4 at a level (though somewhat 

 higher) corresponding to that of the bed containing land and fresh- 

 water shells at Amsterdam, to be alluded to hereafter. Between 

 513 and 775 feet at Utrecht strata were passed through containing 

 Nucula Cobboldioe, Tellina prcetenuis, and the Arctic forms, Leda 

 lanceolata, Oardium groenlandicum, and Natica clausa, with other 

 shells representative of our Upper Crag : these deposits seem to me 

 as recent as the Red Crag horizons of Sutton or Butley. Below 

 this depth, from 775 to 898 feet, were found what I consider to be 



1 The yellow colour of the former may possibly be due to the decomposition 

 of the glauconite. 



2 Lithologically the Diestien and Scaldisien sands are almost identical. 



3 Some of* the beds described by Dr. Lorie seem to be similar in character to 

 the Ohillesford Clay of East, Anglia, though they are of different age. 



4 One specimen only was found at 644 feet. 



